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  • Castelli - Alpha RoS Light Limited Edition Jacket - Women's - Forest Gray/Black
    Castelli - Alpha RoS Light Limited Edition Jacket - Women's - Back
    Castelli - Alpha RoS Light Limited Edition Jacket - Women's - Detail
    Castelli - Alpha RoS Light Limited Edition Jacket - Women's - Detail
Castelli - Alpha RoS Light Limited Edition Jacket - Women's

Castelli Alpha RoS Light Limited Edition Jacket - Women's

47% Off
$132.71 $249.95

Item #CST00Q9


Tech Specs

[membrane/laminate] Windstopper 150, [face fabric] 100% polyester, [liner] 90% polyester, 10% elastane
winter, spring, fall
3 rear, 1 front zip
rear tabs
Claimed Weight:
Recommended Use:
road cycling
Manufacturer Warranty:
1 year

Alpha RoS Light Limited Edition Jacket

In an industry full of acronyms, Castelli adds to it with its Alpha RoS Light Limited Edition Jacket where the RoS stands for Rain or Shine, meaning this jacket offers both wind and water protection in formidable weather and also breathes well enough and manages moisture when conditions are more favorable too. Castelli does a wonderful job of calling out the temperature ranges for its kit and this jacket is well suited to its suggested temperature range of 46 - 59 degrees Fahrenheit. Depending on base layers and personal comfort zone this can of course vary but it's nice to know that this jacket can handle a bulk of our shoulder season rides, rain or shine.

The versatility of this jacket is what really makes it extraordinary. By using highly advanced fabrics, along with reduced seams and sealing them when necessary, this jacket is ideal in cooler dry temps while holding its own on milder, wetter conditions. Castelli calls it functional waterproofing meaning it won't be absolutely dry like an out-an-out rain jacket, however, it will keep you warmer and drier over a wider range of conditions.

Gore's Windstopper 150 membrane is the key to the jacket's versatility, but Castelli's cycling clothing know-how is why it's ideally suited for serious cold-weather training and racing. Part of that is the inclusion of a rear panel of Castelli's Nano Flex Xtra Dry, a thermal material with a DWR treatment that dumps excess heat, improves breathability, and maintains a water-resistant surface across the entire jacket.

The Windstopper layer is separated from a thermal layer across the front panel, so you can unzip the protective shell but leave the thermal layer intact, letting you moderate the exposure on long climbs without baring your chest to frigid, wintery blasts. Skiers and alpinists use Windstopper indiscriminately: their goal is to stay warm and dry at all costs. Cyclists' needs, on the other hand, change over the course of a ride depending on intensity, climbing, descending, etc., so we need the protection to change with us in real time. The Alpha solves that problem.

  • Castelli's versatile jacket for training and racing
  • Windstopper 150 membrane blocks wind and water and remains breathable
  • Rear thermal panel vents and keeps the rain at bay
  • Separate thermal mid-layer provides targeted warmth
  • Slim fit eliminates flapping material during tempo base miles
  • Maintains breathability to manage moisture during hard efforts
  • Raw edge hem and cuffs reduce bulk and maintain coverage
  • Masters of cycling apparel, Castelli knows the needs of cyclists in variable conditions


  • Familiarity: I've used it several times
  • Fit: True to size
  • Size Bought: large

The Castelli Alpha RoS Light jacket makes riding on any day a possibility. The jacket layers well over a baselayer or a jersey and gives you even more pockets-for-snacks.

I've worn the jacket in temps down to about 35, paired with a windstopper jersey, and been quite comfortable. The cuff fits well underneath gloves, helping to avoid the all-too-common discomfort of cuff/sleeve/glove. I was initially skeptical of the liner vest situation, but let me tell you: gamechanger! It makes this jacket even more versatile for temperature ranges of 32-55 degrees Fahrenheit or so.

I'm 5'6" 145lbs, and the large fit well with plenty of room to layer beneath it. A medium also fit, but less ideal for wearing a jersey underneath.

Hi Hannah,

I’m trying to find a jacket for my wife and considering Castelli. She’s 5’6” 151 lbs and 40” in the chest at fullest point. What size would you recommend? I think it would be helpful if everyone listed chest size to give more info for the buyers.


Women's Apparel












































Note: Castelli has a "Euro" slimmer fit. We suggest ordering at least one size larger than your normal US size.
How to Measure:
For best results, take measurements over your underwear.
Measure under your arms, around the fullest part of your chest.
Natural Waist:
Measure around your natural waistline, keeping the tape a bit loose.
Measure around the fullest part of your body at the top of your legs.
Using pants that fit well, measure the crotch seam to the bottom of the leg.