Fly Jack-Sey

The Fly Jack-Sey is so called because it makes use of our latest innovation, FLY Fabric Technologies (FFT). This is a three-layer material with a windproof yet breathable Gore-Tex Infinium^TM Windstopper® inner, then a mid-layer and outer made from 100% recycled material ndash; the insulation being CLIMA SL, which is super light but also very warm, and the outer being FLY SL, which is windproof and treated to shed rain and spray.

The Gore-Tex Infinium^TM is only found at the front, the portion of the vest most likely to encounter the elements, which means that the back of the jersey is cooler, lighter and allows a little more air circulation. The jacket also features a low/no collar cut, which is fitted to stop wind from rushing down the neck and making you chilly, but also allows more heat to escape.

This practical garment is finished like the best Castelli jerseys and jackets, with three back pockets and one zippered valuables pocket, reflective tabs for safety, a waist that stays put in ride position and a zipper that can be opened from the top or bottom, allowing easy venting mid-ride.

Unlike those other layers, though, it hits the sweet spot of keeping you warm and protected, without causing you to overheat, on days when both you and the weather can't make up your minds.