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Insider Jersey - Men's

5 out of 5 stars
3 Reviews
Color:Dark Red


Size Chart


Insider Jersey

Castelli crafts the Insider Jersey specifically for the rigors of indoor training—situations in which cyclists are putting out maximum effort in spaces with limited ventilation and airflow. In order to overcome these limitations, Castelli constructs the jersey from a porous 3D Mesh fabric that lets air move as freely as possible to help you stay cool, regardless of whether you're spinning in the garage, basement, or muggy spare bedroom. This airy material also wicks moisture better than a traditional cycling jersey, keeping sweat at bay to help you stay dry and comfortable when you're cranking out watts. Despite the meshy construction, Castelli paid special attention to not make the Insider Jersey too transparent, meaning it would make a great outdoor jersey for summer rides when the temperatures are approaching triple digits and beyond.


  • An airy mesh jersey designed for indoor cycling endeavors
  • 3D mesh fabric offers maximum airflow without being too transparent
  • Material rapidly wicks to help you stay dry and comfortable
  • Works well as an outdoor jersey for hot-weather rides, too
  • 2 rear pockets for storing riding supplies and essentials
  • Full-length zipper for easy on and off and quick ventilation
  • Item #CST00T3
3D Mesh (100% polyester)
2 rear
Recommended Use
road cycling
Manufacturer Warranty
1 year

Overall Rating

5 based on 3 ratings

Review Summary

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

Fits Slightly Small

Screen reader users: the following list provides a visual scale to illustrate the product fit. Please refer to the heading above for the fit type in text.
Runs smallTrue to sizeRuns large

What do you think about this product?


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5 out of 5 stars

March 12, 2024

Great jersey for indoor cycling

I've used it several times

This jersey is very light and thin. It breathes great. I sized up one size and it fits great. I think it fits true to size, but I don’t like how it would look on.


Originally reviewed on Backcountry.com

5 out of 5 stars

November 10, 2021

Great except bottom hem rolls up (on me)

I've used it several times
Size Bought:
5' 11"

Until I saw this, it never occurred to me to wear anything other than a T-shirt on the trainer. As the other reviewer says, it's great not to have to pull off a dripping wet T-shirt over my head post-workout. And the rear pockets are handy for energy bars during longer sessions. It seemed pricey until I realized: (a) T-shirts are much more expensive than they used to be, and (b) this was on sale at a nice discount. Have used it for a couple of trainer sessions, very comfy. As usual for Castelli, XL fits me well. Although it seems to be made longer in the torso than the other XL SS Castelli jerseys I own. So the elastic hem at the bottom rolls up, a minor annoyance which does not happen with my other Castelli kit. Maybe a wider elastic strip or a shorter design?

John F
5 out of 5 stars

November 8, 2021

Feels good, looks nice

I've used it once or twice and have initial impressions
Size Bought:

Great jersey for indoor training. Fits well, feels good, looks nice. Might help you zwift slightly faster.

Douglas O