Designed for indoor training, Castelli’s Insider Jersey is incredibly lightweight to give you a layer for those tough sessions on the turbo or even in the hot summer sun. Weighing only 88g, the mesh fabric allows for maximum cooling & moisture wicking while not being too transparent that you can’t wear it on the road. There are also pockets on the back to hold everything you’ll need, in or out, & a full-length zip down the front if you need to just take it all off. Perfect for indoor winters & outdoor summers, the Insider Jersey will always be an option.