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CastelliUPF 50+ Light Arm Sleeves


Item # CST00CJ

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  • Black, S ($39.95)
  • Black, M ($39.95)
  • Black, L ($39.95)
  • Black, XL ($39.95)
  • White, S ($39.95)
  • White, M ($39.95)
  • White, L ($39.95)
  • White, XL ($39.95)
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Item # CST00CJ

UPF 50+ Light Arm Sleeves

While most arm coverings are designed to keep you warm, the UPF 50+ Light Arm Sleeves from Castelli can actually keep you cool too. They are rated at UPF 50+, however, Castelli claims that in laboratory tests, they actually blocked 99.8 percent of damaging UV rays. It uses a polyester base that's more effective than typical nylon at blocking UV rays while keeping you dry. Minimal seam construction prevents rubbing and double-sided silicone elastic at the openings ensure they stay in place throughout the ride. They also pack up extremely small so you can stash them into your jersey pocket when they're no longer needed for the day.

  • Solare fabric fends off the chill and the sun's rays
  • UPF 50+ protection keeps arms protected on bright days
  • Polyester based, offering excellent moisture management
  • Double-side silicone elastic up top keeps the warmer in place
Tech SpecsSize
Tech Specs
UPF Rating
Recommended Use
Manufacturer Warranty
1 year


Arm & Knee Warmers





Rider Weight

99.2 - 132.3lb

(45 - 60kg)

99.2 - 132.3lb

(45 - 60kg)

132.3 - 154.3lb

(60 - 70kg)

154.3 - 176.4lb

(70 - 80kg)



Short/Jersey Size XS - S S - M S - M L - XL 2XL - 3XL
Short/Jersey Size:
Take your typical cycling short or bib sizing for comparison.

View more Arm Warmers

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Do the UV sun sleeves work while worn inside out?

No. Wearing them inside out actually causes the inverse to happen. You get more sunburned.

Hello, I am interested in these arm skins.
I have long arms, so I am looking for the length of the sleeves. I have tried similar sun sleeves from pearl izumi and sugoi but they have both been really short. I don't care if I need to order XL and have them fitted to my arms. I typically wear tops in S or M.
Please share the length of your sleeves! thank you!

Hi Edwin, Castelli doesn't list the length on these, but I've used some similar arm warmers from them in medium that covered my long arms just fine.


  • Familiarity: I've used it once or twice and have initial impressions

You should consider to wear sleeves some days and protect your skin, these sleeves will do the job, nothing to complaint, check sizing, these are long

great protection

  • Fit: True to size
  • Size Bought: small

they can get a little warm on a hot day but nothing too bad. helps even wipe the sweat. i got them vs having to put on block so i really like the protection.

Comfortable, and better than sunscreen

  • Familiarity: I've put it through the wringer
  • Fit: True to size
  • Size Bought: xl

I wear long sleeves on almost every ride, so I use these quite a lot. They are more reliable than slippery sunscreen, which sweats off and must be re-applied. In my experience they do not make a ride appreciably hotter, but they go on quickly and do an excellent job of blocking the sun. It provides an evaporative cooling effect so you will get some cooling as you get moving and sweat and/or wet your sleeves.

I like that the silicone grippers are on both sides of the sleeve. It will help keep your jersey sleeves from riding up and enables you to wear the black sleeves inside out if you prefer not to show the logo. The white sleeves keep the sun off just as well but the logo is noticeable when used inside out.

They are not a great alternative to a true warming sleeve - these are lightweight lycra so even if paired with a three-season jersey do not expect them to add any warmth; the wind blows right through them.

I got the XL based on my weight. The sleeves fit fine around my forearms and biceps but are long relative relative to my stubby t. rex arms. Not much I can do about that, so I usually fold them over for a more comfortable fit. The dual-sided gripper makes this work well.

Quick Drying & Cooling Fabric

  • Familiarity: I've put it through the wringer
  • Fit: True to size

Castelli arm skins are a quality product. After two years of use they are still holding up as if they are new. The silicone grippers are in top shape and I love that it is a consistent band of silicone all around the arm opening. I own Gore Bike Wear windstopper sleeves and I've tried Pearl Izumi SPF protection sleeves. These two brands don't have a solid silicone band like the Castelli sleeves. It's a testament to the details that Castelli curated. Granted, the windstopper sleeves are intended for colder weather but the Pearl Izumi are for warm weather. I can tell you the black PI's felt warm when I tried them on whereas Castelli skins has a minty cooling effect in black and white colors. Regarding hot spots, there are none due to flatlock seams. I recommend cutting the washing instruction label, it bunches up and gets annoying.

For reference, I've used these in 105 degree weather last year and they felt great. Not as cool as when it's about 95 degrees but they dried quick and kept my arms from burning and tanning.

If you need any of these Backcountry is the right spot. My local bike shop has to special order them and if you lookout for specials, you can get a pretty sweet deal here.

how does the sizing run?

Erick, what size did you order? Thanks in advance!


  • Familiarity: I've put it through the wringer
  • Fit: True to size
  • Size Bought: large

These arm skins work (mild to warm days), but on intense hot days.... my internal body temperature feels warmer. I was hoping that these skins would cool my arms on those hot days but that's not the case for me.

The fit is good, they are constructed well, and easy to wash.