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Castelli Pro Issue Sleeveless Baselayer - Men's


Pro Issue Sleeveless Baselayer

On days when you know you need something extra under your jersey, but you don't really want to feel an extra layer, grab Castelli's Pro Issue Sleeveless Base Layer. Constructed out of lightweight polyester 3D mesh, the top fits under a jersey and facilitates moisture transfer from your skin to your jersey to keep your temperature regulated on crisp fall days or cool spring mornings. The 3D mesh forms a thin insulating layer next to your skin to keep you warm, and as you heat up, the material will continue to wick away sweat to cool you off. On this year's version, Castelli widened the collar to fit better under aero jerseys and included a flat waist hem along the bottom to prevent chafing or irritation when tucking it into shorts.

  • Castelli's baselayer situated between the Prosecco R and the Pro Mesh
  • 3D mesh fabric creates an air barrier next to your skin for insulation
  • Polyester capillary action wicks perspiration away from your skin
  • Reduced seams at the shoulders improve ride comfort
  • The wider collar fits better under aero jerseys
  • Flat waist hem lies flat under bib shorts
  • Ideal for temps ranging between 50-77 degrees Fahrenheit
  • Item #CST008Z

100% polyester 3D mesh
Insulation Weight
Claimed Weight
Recommended Use
Manufacturer Warranty
1 year

Tech Specs

What do you think about this product?


>Rating: 2

Not happy

Runs small
Size Bought
6` 2"
178 lbs

This runs extremely small. According to the size chart I should wear a XL. I would say I need a XXL or XXXL. I am 6' 2" have a 41 chest 36 waist and 41 hips.

>Rating: 5

Great warm-weather choice

True to size
Size Bought
5` 8"
152 lbs

Very similar to my Rapha Pro Team base layers, possibly a bit lighter and softer in texture. Very comfortable, no scratching or chafing from the seams. Love the closed-mesh design. I sized up to a L following the usual patterns with Castelli kit, could have done a M instead.

>Rating: 4

just exactly right. w/ or w/o sleeves

I have lots of base layers. And if you don't, you should start with this one. Or get the Short sleeve

>Rating: 5

Excellent spring & summer vest baselayer

I've put it through the wringer

Great summer vest baselayer that Castelli "officially" rates for use from 60° to 77°+ F. Very, very light material. Open cell weave: well ventilated material. I really love using this piece when climbing in 60°-80° weather. During steep ascents, I unzip my jersey all the way and this ultralight vest baselayer wicks away sweat and helps keep my chest cool but not totally bare. In weather above 80° (and esp > 90°), personally, I would use Castelli's more open fish-net vest ("core3") baselayer. Sizing: Usually size up +1 with Castelli. Here also. I'm 5'10" and 185. The XL here fit perfect. Wrap around as designed. The size XL could easily fit a rider 180-200 lbs.


I wear a L Castelli jersey. Should I get a L size for this base layer? Or should I get a M because the reviews says True to Size? Also, the product description says this base layer helps keep you warm. So, I'd want to use it on cold days. But the reviews says it's better for warm weather. Is it one or the other? Or both?