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Core Mesh 3 Sleeveless Baselayer - Men's

3.6666666666666665 out of 5 stars
3 Reviews


Size Chart


Core Mesh 3 Sleeveless Baselayer

Castelli believes so much in the power of the fabric it uses to craft the Core Mesh 3 Sleeveless Baselayer that it deviated from its usual performance-related fabric monikers and named it Magic Mesh. Before you get skeptical about the fabric's otherworldly name, consider that the brand omitted all traces of less breathable Lycra when constructing the mesh, using only the most breathable polyester fibers to ensure maximum moisture management. By putting this featherweight layer under your summer jersey, you'll actually help speed up the rate at which moisture is pulled away from your skin to evaporate, helping you stay cooler and drier as you push through hot, humid air.


  • Wear more to stay cooler with this ultralight baselayer
  • Next-to-skin fit ensures constant moisture transfer
  • Airy mesh fabric made only with highly breathable polyester
  • Nearly seamless construction limits likelihood of chafing
  • Item #CST00G8
Magic Mesh (100% polyester)
Insulation Weight
Claimed Weight
Manufacturer Warranty
1 year

Overall Rating

3.5 based on 3 ratings

Review Summary

1 Stars - 0 reviews
2 Stars - 0 reviews
3 Stars - 1 reviews
4 Stars - 2 reviews
5 Stars - 0 reviews

Fits Small

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Runs smallTrue to sizeRuns large

What do you think about this product?


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3 out of 5 stars

July 8, 2024

Castelli - good product, poor fit

Love the product; hate the fit. Ordered 2XL and cut the sleeves and neck because too tight. Regardless, product works very well. FWIW, my chest measures 43-44 in.

james m

Originally reviewed on Backcountry.com

4 out of 5 stars

March 17, 2022

Castelli mesh undergarment

I've put it through the wringer

Like many other reviews, it fits "tight". I'm 6'1" and normally my chest is around 42" around measured under arms to provide context. A L/XL does fit and surprisingly feels good. I particularly like the long length to get down in bibs. I now had a full summer and full winter on it. it's AWESOME for summer, must have and I can only imagine in warmer climates it even more so. I'm in Pacific NW. For Winter, not so much, it doesn't replace a merino base layer for comfort or air insulation. I have washed mine around 40 to 50 times on delicate with kit, but also used delicate low heat drying in tumble dryer and it's going strong. Even still "white". If I had a complaint, I'd like it in long sleeves and a dark color. It's under the jersey so color for light shouldn't matter, and I'm not fond of "white". I'd say for friends in the warmer states, southern U.S. with humidity and temperature, this is a MUST HAVE. Good luck, and as always backcountry gearheads were awesome to work with.

MC M71

Originally reviewed on Backcountry.com

4 out of 5 stars

December 4, 2020

Open mesh; runs VERY small

Size Bought:
5' 11"

I bought this and the Craft Mesh Superlight to compare. Two things: (1) This is open mesh, like a net, unlike the Craft and other "mesh" base layers I have. I bought this, in part, for indoor riding on the trainer, and, while it's light, not sure it'll stop the sweat from pouring off, due to the holes. (2) As others have written, it runs even smaller than other Castelli gear. I have around a 37" chest, and the S/M is tight. Castelli's race jersey in S is snug on me, so I usually wear a M, but this S/M is even tighter than the S race jersey. In comparison, the Craft in S fits me quite well. To be clear, I have not tried it out yet, so these are just initial impressions out of the box.

Andrew W