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  • Castelli - Core Mesh Base Layer - Short-Sleeve - Men's -

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  • Castelli - Core Mesh Base Layer - Short-Sleeve - Men's -

Castelli Core Mesh Base Layer - Short-Sleeve - Men's

Temporarily Out Of Stock

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6 Reviews


The core of your kit.

Castelli's Core Mesh Base Layer incorporates an update to the classic fishnet style design. While the older design used the holes of what felt like real fishnet to trap air between the skin and the second layer of clothing, the updated version uses a soft mesh that comfortably wraps your upper body as you ride.

However, with the new fully-open mesh design, it still serves to hold the jersey off of the skin. Essentially, this creates a layer of air between your skin and the jersey in order to help you maintain a constant body temperature. But, besides these thermo-regulating properties, the improvements that Castelli brings to the table are several. The mesh is made from a polyester hollow core fiber that's soft-to-the-touch, efficiently wicks away moisture, and has ample stretch. In terms of shape, Castelli calls this 'body wrap,' because it's designed to wrap the body so that the gaps are only in the mesh, not between the mesh and the body. Accordingly, the entire base layer is mesh, save the hems and the 'V' that resides just below the collar.

The Core Mesh is cut long in order to stay comfortably tucked inside your shorts and bibs. Additionally, it was constructed with minimal seams for a maximum level of comfort.

The Castelli Core Mesh Base Layer is available in the color White and in the sizes Small/Medium, Large/X-Large, and XX-Large.

  • Item #CST2597

Tech Specs

[body] mesh
form fit
Recommended Use
Manufacturer Warranty
1 year

Tech Specs

  • Reviews
  • Q & A

What do you think about this product?

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Fishnet Fabric?!

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

I was seriously surprised when I opened the package here. This is basically fishnet. Sure, it breathes really well... because there's no fabric there.

The principle here makes sense; the fabric is meant to pull moisture away from the body but breathe really well. Either way (and in practice), I can't stand wearing half a shirt, especially when the rubbing and chafing caused by said material is worse than normal. I give it two stars because it doesn't suck at it's intended purpose, there are just countless other options that do the job just as well and don't have this same construction.

EDIT: After using it more, I'm bumping it to 3 stars. Absolutely adequate and at the price a very reasonable option. Seems to achieve its intended purpose well. Bought a few more and they all varied in length though, some are like a dress, some are barely long enough. Nicer packaging than quality control on this one.


  • Familiarity: I've used it several times
  • Fit: True to size
  • Size Bought: L/XL
  • Height: 5'11"
  • Weight: 195lbs

A fairly new piece in the wardrobe, I was given one of the original Castelli mesh underlayer shirts when they first came out years ago, and the current ones are by comparison, fantastic! Great wicking, comfortable, snug but stretches well, doesn't ride up, light, the whole deal. I rarely ride without an underlayer these days, and this is one of the best for warm weather. If it wears as well as my original, it'll be an exceptional investment.

Really Cool Shirt

  • Familiarity: I've used it several times
  • Fit: True to size
  • Size Bought: Small/Medium
  • Height: 5'7"
  • Weight: 130lbs

I echo everything said in the previous reviews, especially about the "see through" nature of the shirt. One thing that hasn't been mentioned, wearing an undershirt like this is a great way to help keep arm warmers up (if you're like me and have issues with that). I'm 5'7" and 130lbs, size S/M fit perfectly. I was afraid it would be too big, but the shirt is very stretchy.

A favorite undershirt.

  • Familiarity: I've put it through the wringer
  • Fit: True to size
  • Size Bought: L/XL
  • Height: 6'0"
  • Weight: 170lbs

The Castelli mesh is the best out there. Breathes super well and creates a layer of cool air on warm to hot days. They are also well made and last a while as long as you take care of them. I wash mine in a garment bag and they have lasted a long time. I just wish they were an inch longer in length, but they're still close to perfect.

Good product

  • Familiarity: I've used it several times

I bought this about a few weeks ago and have used it several times so far under a couple different jerseys. It does almost exactly what the description says. I have noticed my temperature staying a bit more constant, and it definitely does a great job wicking away sweat. The only thing, be ready for how meshy it is. The picture just cannot prepare you for how see-through it is. Granted, it is a base layer, but just be warned.