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CastelliAlpha RoS 2 Light Jacket - Men's


Item # CSTZ7G1

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Item # CSTZ7G1

Why We Like The Alpha RoS 2 Light Jacket

Be seen in brilliant orange contrast through dark, wintery mist and rain showers with the Castelli Alpha RoS 2 Light Jacket. The lightweight shell protects you from irritating transitional weather as you roll towards summer. With honor, it inherits all the winning qualities of the Alpha RoS 2, but in a more breathable, lightweight design. GORE-TEX on the front and sleeves shields your torso from misty rain and chilled wind, while the lighter insulating layer of the RoS 2 Light manages to keep you comfortable in on hard-hitting training rides as body-heat builds. Nano Flex Xtra Dry on the back adds a thin barrier that repels rain while promoting additional heat loss and sweat evaporation.

The extremely versatile shell begs to be so much more as the three rear pockets provide ample room for valuables and snacks. The semi-fitting cut allows room for your favorite baselayer or training jersey without a sacrificing range of motion or freedom.

  • A transitional weather performance jacket for dedicated riders
  • Ideal complement to the Alpha RoS 2 Jacket
  • Nanotechnolgy on back sheds water while letting heat escape
  • Alpha double layer construction seals out wind and mist on the road
  • Inner insulation of lightweight Prosecco Strada manages heat build-up
  • Suited well training rides ranging from 45-59 degrees F

Tech Specs
MaterialDouble Layer Alpha, [inner] insulating, [outer] GORE-TEX INFINIUM WINDSTOPPER 150
Lengthwaist with drop tail
Venting[back] venting channels
Pockets3 rear, 1 front zippered
Reflective[pockets] laser-cut drainage holes
Manufacturer Warranty1 year


Men's Apparel




















































How to Measure:
For best results, take measurements over your underwear.
Measure under your arms, around the fullest part of your chest.
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.

What do you think about this product?


>Rating: 5

Accurate sizing

True to size
Size Bought
5` 9"
175 lbs

Every review of this light jacket as well as the ROS 2 jacket say the sizing runs absurdly small. I have found that to not be the case. I’m 5’9” 175lbs with an athletic build. Broad shoulders, and wear a size 32 pants. I bought a size large and the jacket fits excellent. Snug, slim fit, but not restrictive at all and no excess material. It you like your cycling clothing to fit as cycling clothing is supposed to fit, then the sizing is spot on in my opinion. Haven’t had a chance to use the jacket yet to comment on the performance but the quality and fit is A1. Can’t wait to put it to use.

>Rating: 4

Great Jacket - but not eco cred

I've used it several times
Runs small
Size Bought
6` 1"
164 lbs

Have owned the Gabba - and found it to be overhyped - turns into a sponge at a certain point. This jacket does what it says - have used it in 45ish degrees with big wind chill and it was fine with a mid weight base layer. If heavy rain a possibility would carry a shake dry shell to put over - only thing that doesn’t rely on DWR which inevitably doesn’t last. Fits tight - in fact when I put it on initially it felt too tight - till i got on the bike where it was perfect. Will see how durable it is - only used a few times - had to dock it a star given no apparent effort to consider enviro design - I mean its 2021!

>Rating: 5

Just a great jacket

I've used it several times
Runs small
Size Bought
5` 11"
148 lbs

This fits slightly smaller than most other Castelli gear. I have an older small Gabba and small Castelli jerseys and shorts but am fairly certain small in this would be too snug. Medium is perfect for me in this one and for the sort of riding I'm doing in it (training, not racing); it's close fitting but not a sausage-skin. I was looking for a late winter / early spring jacket for Toronto weather (0C-10C say) and have to say this is a great bit of kit for that temperature range (which is a bit cooler than Castelli suggests; I couldn't imagine wearing this at 15C!). You can adjust for different conditions with your base layer (Merino to polypro) and it really does both block the windchill yet breath far better than something like the Gabba. The orange colour is also great, especially for this time of the year. It's a great looking and great performing jacket, and also nicely water resistant (although that's based on running my arm under the faucet rather than an extended rain ride, but it does have taped seams and I've had good luck with Infinium on other gear, so I'm optimistic!). Looking forward to more spring/fall riding in this.

>Rating: 5

Versatile jacket

I've used it once or twice and have initial impressions
Runs small
Size Bought
5` 10"
170 lbs

First, let’s get sizing out of the way. It’s typical castelli sizing. I’m 5’10, 170lbs and a medium fits like it was made for me. I purchased this jacket because I was missing a piece that could do well on hard training rides in the upper 30s to upper 40s. My Alpha RoS handles anything colder very well and I have plenty of clothing for 50+. That being said, I rode in this for the first time today with an ASSOS winter base layer and it excelled in 35 degree weather. I really like how the front is windproof and the back is more breathable; my base layer wasn’t wet at the end of my ride. With the correct base layer, I think that this may be one of the most versatile jackets out there. I also wanted something more visible without looking like a highlighter and the bright orange fills that need perfectly. If you’re considering this jacket, just buy it; you won’t regret it.

>Rating: 4

Nice Addition to a Winter Kit

I've used it several times
Runs small
Size Bought
5` 8"
176 lbs

Overall a good addition to winter riding. I've used this in upper 30s, lower 40s degree F dry weather with good results. Base layering is key, as well as using a long sleeve jersey underneath. It breaths well, yet maintains your core temperature. The usual Castelli smaller-than-normal sizing: I'm 5'8", 176 lbs with a 40" chest and the XL fits me well (snug everywhere, but not too tight). Back pockets are right-sized, the lower-left zipper pocket is a secure spot for car keys. The bright red is perfect for visibility, the sleeves long enough to cover past my wrists, and the rubberized bottom hem ensures it doesn't creep up. It's pricey, but the construction is impeccable and I would expect it to wear well over the years.

>Rating: 4

Perfect for PNW rain rides

I've used it several times
Runs small
Size Bought
6` 0"
185 lbs

I've had an original Castelli Alpha for a few years now and love it. But, it was a little too warm for the 42-50 degree days that are typical in Oregon winters. This new RoS light edition is perfect for what and how I ride. Water repellency seems to be very good so far and the lighter weight means that a little warmer glove and hat combo works without cooking me. The side pocket for a phone is convenient, but just a bit difficult to zip while moving. I'm a fan of Castelli jackets and this is one of the best. True to Castelli sizing, I'm an XL here, am size large in Rapha.