Airplane Window Seat Sunscreen: What the In-Flight UV Measurements Found

Affiliate links below, but they cost you nothing extra. We only point you to what the ingredient lists actually back up.

One number does all the work in every article about flying and your skin. It’s 56.6 minutes, and it comes from a real research letter in a real journal, so it gets quoted forever: “Pilots flying for 56.6 minutes at 30 000 feet receive the same amount of UV-A carcinogenic effective radiation as that from a 20-minute tanning bed session.” ^[1] Two things almost never travel with it. That reading was taken in the pilot’s seat of a single-engine turboprop, through a 1.6 cm acrylic windshield, around midday in April. ^[1] And when a different team carried a radiometer down the aisle of airliners in flight, the cabin readings came back empty.

The cockpit and the cabin are two different measurements

Answer first: most in-flight UV research put its sensor on the flight deck, one study also walked it through the cabin, and those two places did not give the same answer.

Study	Where the sensor was	What was flying
Cadilhac and colleagues, 2017 [8]	The cabins, plus Airbus and Boeing 777 cockpits	14 flights, July to October 2016
Sanlorenzo and colleagues, 2015 [1]	Pilot seat, behind a 1.6 cm acrylic plastic windshield	One Socata TBM850, a general aviation turboprop
Baczynska and colleagues, 2020 [9]	Pilots, measured as accumulated dose	322 short-haul flights, A321-231 and A320-214
Emslie and colleagues, 2025 [4]	Each of the 6 cockpit windshields, plus dose at pilots’ skin	15 Airbus A320/A321 jets, across 39 flights
Schennetten and colleagues, 2019 [5]	Behind the windshield surfaces and at the pilot’s position	Several commercial windshields under flight conditions

That imbalance is the single most useful thing to know here. This is occupational research, collected to answer a workplace question about people who fly for a living, and the flight deck is where the workplace question lives. Only one of these teams was asking about the rest of the aircraft.

One more piece of bookkeeping, because it changes who you should believe. The often-quoted transmission range for aircraft windshields, “UV-A (320-380 nm) transmission ranged from 0.41% to 53.5%, with plastic attenuating more UV radiation than glass,” is not something the 2014 authors measured. They’re quoting a 2007 Federal Aviation Administration report on windscreens. ^[1] We couldn’t get the FAA report itself, so we’re citing the research letter that repeats it, and we’re telling you it’s secondhand rather than pretending we read the survey.

Does the window next to my seat let UVA through?

One team went and checked, and found nothing in the cabin.

The 2017 study used “a three sensor-integrated electronics UV radiometer (A, B, and C) during 14 flights from July to October 2016,” with readings “performed during daylight hours once the airliner had reached cruising altitude.” The result, in full: “We failed to find UVC radiation. The measurements detected neither UV A nor B in any parts of the cabins of the planes tested, nor in the Airbus cockpits. UVA radiation was however found in the cockpit of Boeing 777s. But UVA levels remained well below the values found at ground level and they were also strongly reduced (more than 10 times) by cockpit sun visors.” ^[8]

That’s the closest thing to a direct answer that exists, so hold it with its edges showing. It’s one study, 14 flights, four months of one year, daylight hours, at cruising altitude, on the aircraft those authors happened to fly. The abstract names the Airbus and the Boeing 777 and no others, and we couldn’t open the full paper, so we can’t tell you which specific types or how many windows. The authors open their own discussion with “Few studies have assessed the level of UV radiation in an airplane.” ^[8]

The general story about window glass stopping UVB while passing UVA is one we’ve already told at length for cars, so here it gets one line and a pointer: that’s the mechanism behind our guide to Korean sunscreen for driving, and an aircraft is a different material and a different question.

Up front, the answer really does vary. The 2025 Airbus study covered each of the 6 cockpit windshields in 15 A320 and A321 jets across 39 flights, and its result splits by panel: “All front windshields blocked UVA effectively. Several cockpit side and rear windshields allowed transmission of UVA above approximately 350 nm.” Where a panel performed poorly and direct sun came through it, the authors recorded “UVA1 (340-400 nm) doses of up to 2.29 mW · cm-2 on exposed skin,” while diffuse scattered light inside the cockpit “contributed negligible levels of UVA.” ^[4] A 2019 German Aerospace Center and Lufthansa study reached the same shape of conclusion from a different set of panels: “Only one of the investigated windshields showed good UV-A attenuation.” ^[5]

Set the empty cabin readings next to the cockpit findings and it can look like a contradiction, so it’s worth saying that the 2017 authors did not read it that way. Their own line about the earlier windshield work is “Our study strongly confirms these results.” ^[8] Different panels, in different places, on different aircraft, measured with different instruments, is enough to produce all of these numbers at once. What none of it supports is one flat sentence about what an aircraft window does.

Am I getting more UV at 35,000 feet than I would on the ground?

Higher up means more UV, and there is a published rate for it, but the published rate is about mountains rather than cruising altitude.

The WHO’s practical guide to the UV index puts it plainly: “At higher altitudes, a thinner atmosphere absorbs less UV radiation. With every 1000 metres increase in altitude, UV radiation levels increase by 10% to 12%.” ^[6] Everywhere that guide repeats the rate, it puts it in a mountain and ground-level setting, and it never applies it to an aircraft. ^[6] That’s a hiking and skiing figure. Multiplying it out to nine kilometres up would be our arithmetic rather than the WHO’s finding, so we’re not doing it. If you want the ground version of this, we wrote it up for high altitude hiking.

What we can show you instead is the actual table, because the 2014 team measured at eight altitudes in one climb. These are the readings at the pilot seat, in microwatts per square centimetre, on the meter that covers both UV-A and UV-B. The separate UV-B-only meter read zero at every single altitude in both locations. ^[1]

Altitude	San Jose, California	Las Vegas, Nevada
Ground level	137	127
2,500 ft	135	128
6,000 ft	138	132
10,000 ft	189	182
15,000 ft	228	not available
20,000 ft	234	212
25,000 ft	250	210
30,000 ft	not available	242

That’s one small aircraft, one windshield, one month, two cities, and a sensor in the pilot’s seat. The same paper adds a condition that pushes the other way: “These levels could be significantly higher when flying over thick cloud layers and snow fields, which could reflect up to 85% of UV radiation.” ^[1] Reflected snow is the same problem we covered in our winter and ski guide, seen from above.

Now the comparison that answers the question, and it comes from the flight deck rather than the cabin, because that’s where the dose studies were run. The 2017 team reports that even the UVA they did find, in Boeing 777 cockpits, “remained well below the values found at ground level.” ^[8] A 2020 study measured accumulated pilot exposure across 322 short-haul flights and concluded that “The average monthly exposures were low and significantly below weekend recreational exposures of UK office workers over a similar period.” ^[9] That’s pilots, on the flight deck, compared against ordinary people having ordinary weekends. It isn’t a measurement of you, and it points the same direction as the empty cabin readings.

The same 2020 paper keeps its own exception in view, so we will too: “On 27 single sector flights, UV-A exposure could have exceeded the ICNIRP guidance if eye protection was not used.” ^[9] That’s eyes, on the flight deck, on 27 flights out of 322.

Why pilots and cabin crew keep turning up in melanoma studies

Because the cohort numbers are real and have been replicated, and because the reason for them is still open.

Two independent meta-analyses land in the same place. The 2015 one pooled 19 studies and more than 266,431 participants, reporting a standardized incidence ratio of 2.21 (95% CI, 1.76 to 2.77) for any flight-based occupation, and concluding that “Pilots and cabin crew have approximately twice the incidence of melanoma compared with the general population.” ^[2] A 2019 review by a different group found that “The pooled SIR (pSIR) for melanoma in pilots was 2.03 [95% confidence interval (CI) 1.71-2.40] and in cabin crew it was 2.12 (95% CI 1.71-2.62).” ^[10] Two teams, two searches, the same rough doubling.

Both are careful about what sits underneath. The 2019 review notes it included “12 studies with data collected mostly between the 1970s and 1990s” and closes with a warning that gets left out of most write-ups: “However, most of the evidence was collected several decades ago and their relevance to contemporary levels of risk is uncertain.” ^[10] Death rates also split by job in both reviews. For melanoma mortality the 2019 figures are “1.99 (95% CI 1.17-3.40)” for pilots and “1.18 (95% CI 0.73-1.89)” for cabin crew ^[10], and the 2015 review put the cabin crew mortality ratio at “0.90 (95% CI, 0.80-1.01; P = .97; 2 records).” ^[2]

A commentary in JAMA Oncology went through the candidate explanations and knocked most of them down. On cosmic radiation: “Thus, it seems unlikely that cosmic radiation exposure is relevant in the observed increase in melanoma in this population.” On what the source studies could not adjust for: “it was not possible to control for certain potentially confounding factors such as aggregate flight time, Fitzpatrick skin type, and lifestyle.” And a detail that reframes the whole thing, since air traffic controllers get similar screening and similar pay but never leave the ground: “Flight crew and air traffic control officers undergo similar health screenings and have similar socioeconomic status, and both have an increased risk of developing melanoma even though air traffic control officers are not occupationally exposed to high-altitude flight.” ^[3]

On the UV explanation specifically, that commentary is blunt: “The additional UV-A exposure for pilots offers a possible explanation for their increased incidence of melanoma but does not account for the increased risk for the cabin crew.” ^[3] The 2017 measurement team, having found nothing in the cabins, went further, writing that their study “suggests that increased incidence of melanoma and mortality by this type of illness found among pilots and airline cabin crews may not be related to in-flight UV radiation exposure.” ^[8] Note the hedge in that sentence. They wrote “may not be,” and we’re not upgrading it. The commentary’s own verdict on the whole question: “Multiple hypotheses have been proposed, but the etiology of the increased incidence of melanoma among aircrews remains largely unexplained.” ^[3]

None of that is a statement about somebody who takes four flights a year, and an occupational cohort finding is not a warning for holidaymakers.

So what would I actually do on a long daytime flight?

Nothing here is a reason to change what you do on the plane, and we’d rather say that than sell you a habit.

Put the measured facts in one place. In the cabin, the one team that looked found neither UVA nor UVB. ^[8] On the flight deck, some panels let UVA through and some didn’t, and the doses that were recorded came in below ordinary ground-level and weekend exposure. ^[8][9] The only interventions anybody tested were cockpit ones, and they worked: “The use of shielding blinds on side windshields blocked UVA transmission effectively,” and a pilot’s visor “was very effective in terms of UV-A reduction,” with the 2017 team recording a reduction of “more than 10 times” from cockpit sun visors. ^[4][5][8]

And the recommendations in this literature are addressed to a specific job. One reads: “Pilots should be encouraged to wear sunscreen on exposed skin and use side windshield visors if skin is in the direct light beam.” ^[4] The 2014 letter closes with “We strongly recommend the use of sunscreens and periodical skin checks for pilots and cabin crew.” ^[1] Both name aircrew. Neither names passengers, and widening them to passengers would be our claim rather than theirs.

So if you’re packing sunscreen for a trip, pack it for the trip. The walk across the apron, the taxi queue, the first afternoon somewhere sunnier than home: that’s ordinary daytime sun, and it’s the part of the journey the evidence actually speaks to. This is an editorial guide rather than medical advice, and nothing we read supports being anxious about the flight itself.

What an airplane window seat sunscreen would have to prove

It would have to beat a cabin measurement that came back empty, so there’s no such product category, and what follows is a travel bottle rather than a flight one.

Round Lab Birch Juice Moisturizing Sunscreen. We counted 35 entries on its INCIDecoder page, and exactly two of them are classed there as sunscreen filters: diethylamino hydroxybenzoyl hexyl benzoate, sold as Uvinul A Plus, and bis-ethylhexyloxyphenol methoxyphenyl triazine, sold as Tinosorb S. ^[7] Both are filters with UV-A coverage, and neither is available in a US over-the-counter sunscreen, which is the practical reason a Korean list often looks different from an American one. The page carries one highlight flag, read by eye rather than by search: alcohol-free. There is no fragrance-free flag on it, and the list does include two botanical oils, chamomile flower oil and pine leaf oil. ^[7] We took this bottle apart properly in our full Round Lab Birch Juice review. If you want it, YesStyle stocks the 50ml tube.

We pulled two Korean reviews of this bottle and they land in opposite places, so here are both. Neither reviewer was writing about a flight, and neither mentions a plane at all, so treat them as notes on texture and wear rather than on anything that happens at altitude. One of the two we’ve quoted before, in our guide to sunscreen for flaky skin patches, and we’d rather tell you that.

The disagreement is the useful part, and notice that the first review is itself split. That reviewer won’t re-buy it because it turns shiny on oily skin, and still ends by saying it’s exactly right for anyone after something hydrating and gentle with no white cast. The second is on a repeat purchase, picked for having no white cast and no eye sting. Both are describing the same formula, so if your skin runs oily that’s the thing to weigh, and the filter list won’t tell you which way it’ll go for you.

Now the limit on the product paragraph, in the same breath. Two UV-A filters on an ingredient list is a fact about the list, and it is not a reason to buy anything because you’re flying. It’s a reason to have decent sunscreen with you when you land, which is the same reason you’d have it on any other day. If you’re heading somewhere you’ll be in water, our water resistant picks are the more useful page for the rest of that trip.

FAQ

Am I getting a meaningful UV dose in a window seat?

The one team that measured inside airliner cabins didn’t detect any. Their report is that “The measurements detected neither UV A nor B in any parts of the cabins of the planes tested, nor in the Airbus cockpits,” across 14 flights flown in daylight at cruising altitude between July and October 2016. That’s a single study on the aircraft those authors flew, so it isn’t the last word, but it’s the only direct answer anyone has published and it points at no.

Do I need to wear sunscreen on a plane?

Nothing we read tells passengers to. The two recommendations in this literature are both written for aircrew, one of them word for word as “Pilots should be encouraged to wear sunscreen on exposed skin,” and the cabin measurements came back empty. Pack sunscreen for where you’re going rather than for the flight.

If I close the window shade, does that solve it?

There wasn’t a problem in the cabin for it to solve, going by the one study that looked. Shades themselves were never tested in anything we read, though their cockpit equivalents were, and those worked: sun visors cut cockpit UVA by “more than 10 times” in the 2017 study, and the 2025 study found that “The use of shielding blinds on side windshields blocked UVA transmission effectively.” Those are flight deck results on flight deck panels.

Am I at the same risk as a pilot or a flight attendant?

No, and the studies don’t claim that. Two separate meta-analyses put melanoma incidence in aircrew at roughly twice the general population, and both draw on cohorts of people with career-length flight hours. The newer one warns that “most of the evidence was collected several decades ago and their relevance to contemporary levels of risk is uncertain,” and a commentary on the older one says the cause “remains largely unexplained,” pointing at screening frequency, socioeconomic status, and confounders nobody could adjust for. Air traffic controllers, who never fly, show an increased risk too.

What should I look for on the bottle if I fly a lot?

The same things you’d look for anywhere, since there’s no flight-specific criterion to look for. The one cabin measurement found nothing to test against, so anything marketed on that basis is ahead of the evidence. Choose for the place you’re landing in.

Sources

In-flight measurements, each opened and read on 2026-07-29:
[8] Cadilhac P, Bouton MC, Cantegril M, Cardines C, Gisquet A, Kaufman N, Klerlein M. “In-Flight Ultraviolet Radiation on Commercial Airplanes.” Aerosp Med Hum Perform. 2017;88(10):947-951. doi:10.3357/AMHP.4852.2017. PMID 28923144. Abstract read in full; the paywalled full text was not opened, so only abstract sentences are quoted here, and the abstract names no aircraft beyond Airbus and the Boeing 777. Quoted: “Measurements were taken with a three sensor-integrated electronics UV radiometer (A, B, and C) during 14 flights from July to October 2016.”; “They were performed during daylight hours once the airliner had reached cruising altitude.”; “We failed to find UVC radiation. The measurements detected neither UV A nor B in any parts of the cabins of the planes tested, nor in the Airbus cockpits. UVA radiation was however found in the cockpit of Boeing 777s. But UVA levels remained well below the values found at ground level and they were also strongly reduced (more than 10 times) by cockpit sun visors.”; “Few studies have assessed the level of UV radiation in an airplane.”; “Our study strongly confirms these results and suggests that increased incidence of melanoma and mortality by this type of illness found among pilots and airline cabin crews may not be related to in-flight UV radiation exposure.” link
[1] Sanlorenzo M, Vujic I, Posch C, Cleaver JE, Quaglino P, Ortiz-Urda S. “The Risk of Melanoma in Pilots and Cabin Crew: UV Measurements in Flying Airplanes.” JAMA Dermatol. 2015;151(4):450-452. doi:10.1001/jamadermatol.2014.4643. Full text read, including both tables. Quoted: “We first measured UV radiation in the pilot seat inside a general aviation turboprop airplane (Socata TBM850) through the acrylic plastic windshield (1.6-cm thick) at ground level and at 2500, 6000, 10 000, 15 000, 20 000, 25 000, and 30 000 feet above sea level.”; “The measurements were taken in 2 locations with different solar exposures: San Jose, California, and Las Vegas, Nevada, around midday in April.”; “Our measurements inside the airplane revealed that the windshields blocked UV-B but allowed UV-A transmission.” The Las Vegas figure of about 242 µW/cm² of UV-A at 30,000 feet is given in the next sentence of the same paragraph, where the unit is printed with a superscript 2. Also quoted: “Pilots flying for 56.6 minutes at 30 000 feet receive the same amount of UV-A carcinogenic effective radiation as that from a 20-minute tanning bed session.”; “These levels could be significantly higher when flying over thick cloud layers and snow fields, which could reflect up to 85% of UV radiation.”; “We strongly recommend the use of sunscreens and periodical skin checks for pilots and cabin crew.” The Table 1 values reproduced above are from the UV-A and UV-B column; the UV-B only column reads 0 at every altitude in both cities. The windshield transmission range “UV-A (320-380 nm) transmission ranged from 0.41% to 53.5%, with plastic attenuating more UV radiation than glass” is quoted by these authors from their reference 3, an FAA report (Nakagawara VB, Montgomery RW, Marshall JW, Optical Radiation Transmittance of Aircraft Windscreens and Pilot Vision, Federal Aviation Administration, 2007), which we did not open. link
[9] Baczynska KA, Brown S, Chorley AC, O’Hagan JB, Khazova M, Lyachev A, Wittlich M. “In-Flight UV-A Exposure of Commercial Airline Pilots.” Aerosp Med Hum Perform. 2020;91(6):501-510. doi:10.3357/AMHP.5507.2020. PMID 32408934. Abstract read in full; full text not opened. Quoted: “The in-flight UV exposure of pilots was measured on 322 Monarch Airlines short-haul flights on the Airbus A321-231 and Airbus A320-214 to 31 destinations, mostly in Europe, from 4 UK airports in September 2016-August 2017.”; “For most of the flights, the UV-A exposure was also low.”; “On 27 single sector flights, UV-A exposure could have exceeded the ICNIRP guidance if eye protection was not used.”; “The average monthly exposures were low and significantly below weekend recreational exposures of UK office workers over a similar period.” link
[4] Emslie NA, Liley JB, Johnston P. “Pilot Ultraviolet A Exposures in the Cockpit of Flying Commercial Aircraft.” Aerosp Med Hum Perform. 2025;96(9):803-809. doi:10.3357/AMHP.6647.2025. PMID 40925638. Abstract read in full; the paywalled full text was not opened, so only abstract sentences are quoted here. Quoted: “A spectrometer was used to measure in-flight spectral transmission through each of the 6 cockpit windshields in 15 Airbus A320/A321 jets, across 39 flights, most originating in or destined for Auckland, New Zealand.”; “All front windshields blocked UVA effectively. Several cockpit side and rear windshields allowed transmission of UVA above approximately 350 nm.”; “Diffuse, scattered light in the cockpit contributed negligible levels of UVA, but direct light through a poorly attenuating windshield allowed UVA1 (340-400 nm) doses of up to 2.29 mW · cm-2 on exposed skin.”; “The use of shielding blinds on side windshields blocked UVA transmission effectively.”; “Pilots should be encouraged to wear sunscreen on exposed skin and use side windshield visors if skin is in the direct light beam.” link
[5] Schennetten K, Meier MM, Scheibinger M. “Measurement of UV radiation in commercial aircraft.” J Radiol Prot. 2019;39(1):85-96. doi:10.1088/1361-6498/aaf2a7. PMID 30524082. German Aerospace Center and Lufthansa. Abstract read; full text not opened. Quoted: “Only one of the investigated windshields showed good UV-A attenuation.”; “The use of the visor for filtering direct sunlight was very effective in terms of UV-A reduction.” link

Cohort evidence and its critique, read 2026-07-29:
[2] Sanlorenzo M, Wehner MR, Linos E, et al. “The risk of melanoma in airline pilots and cabin crew: a meta-analysis.” JAMA Dermatol. 2015;151(1):51-58. doi:10.1001/jamadermatol.2014.1077. PMID 25188246. Abstract read in full. Quoted: “Of the 3527 citations retrieved, 19 studies were included, with more than 266 431 participants.”; “The overall summary SIR of participants in any flight-based occupation was 2.21 (95% CI, 1.76-2.77; P < .001; 14 records).”; “The summary SMR for cabin crew was 0.90 (95% CI, 0.80-1.01; P = .97; 2 records).”; “Pilots and cabin crew have approximately twice the incidence of melanoma compared with the general population.” link
[10] Miura K, Olsen CM, Rea S, Marsden J, Green AC. “Do airline pilots and cabin crew have raised risks of melanoma and other skin cancers? Systematic review and meta-analysis.” Br J Dermatol. 2019;181(1):55-64. doi:10.1111/bjd.17586. PMID 30585313. Abstract read in full; full text not opened. This is an independent second meta-analysis by a different group, not an update of the 2015 one. Quoted: “12 studies with data collected mostly between the 1970s and 1990s were eligible for inclusion.”; “The pooled SIR (pSIR) for melanoma in pilots was 2.03 [95% confidence interval (CI) 1.71-2.40] and in cabin crew it was 2.12 (95% CI 1.71-2.62).”; “For pilots, the pooled SMR for melanoma was 1.99 (95% CI 1.17-3.40) and for cabin crew it was 1.18 (95% CI 0.73-1.89).”; “However, most of the evidence was collected several decades ago and their relevance to contemporary levels of risk is uncertain.” link
[3] Shantha E, Lewis C, Nghiem P. “Why Do Airline Pilots and Flight Crews Have an Increased Incidence of Melanoma?” JAMA Oncol. 2015;1(6):829-830. doi:10.1001/jamaoncol.2015.0933. PMID 26181192. Full text read via PubMed Central. Quoted: “Thus, it seems unlikely that cosmic radiation exposure is relevant in the observed increase in melanoma in this population.”; “it was not possible to control for certain potentially confounding factors such as aggregate flight time, Fitzpatrick skin type, and lifestyle.”; “Flight crew and air traffic control officers undergo similar health screenings and have similar socioeconomic status, and both have an increased risk of developing melanoma even though air traffic control officers are not occupationally exposed to high-altitude flight.”; “The additional UV-A exposure for pilots offers a possible explanation for their increased incidence of melanoma but does not account for the increased risk for the cabin crew.”; “Multiple hypotheses have been proposed, but the etiology of the increased incidence of melanoma among aircrews remains largely unexplained.” link

Altitude guidance, PDF opened 2026-07-29:
[6] Global Solar UV Index: A Practical Guide. World Health Organization, WMO, UNEP and ICNIRP (WHO/SDE/OEH/02.2). Quoted: “At higher altitudes, a thinner atmosphere absorbs less UV radiation. With every 1000 metres increase in altitude, UV radiation levels increase by 10% to 12%.” The guide restates the same rate in its messaging section, where the sentence opens with the words “In the mountains”. The same document also states the relationship at a finer step elsewhere, as a 4% increase for each 300 metre gain, so the 10% to 12% figure quoted here is the per-1000-metre wording rather than the only wording in the guide. Every place the rate appears, it is given in a ground-level or mountain context, and the guide does not apply it to aircraft cruising altitude. link

Ingredient list, counted by hand on 2026-07-29:
[7] ROUND LAB Birch Juice Moisturizing Sunscreen, INCIDecoder. The count came to 35 entries. The two items the page classes under the Sunscreen function are Diethylamino Hydroxybenzoyl Hexyl Benzoate and Bis-Ethylhexyloxyphenol Methoxyphenyl Triazine; the birch sap entry is listed as Betula Platyphylla Japonica Juice (1,128 Ppm). The highlight tags were read by eye rather than by search, and there is exactly one, “#alcohol-free”; there is no fragrance-free tag, and Anthemis Nobilis Flower Oil and Pinus Sylvestris Leaf Oil both appear on the list. INCIDecoder carries eight near-identical Round Lab Birch Juice sunscreen and sun cream entries; the one read here is the entry at the URL below, which is also the entry our earlier Round Lab review used. The page records its upload date as 07/06/2022, so treat it as that version of the formula. link

Topics: Hiking & Altitude · Indoor & Window UV · No White Cast · Round Lab · Travel · Winter & Snow · All topics