The Go W Jacket from Castelli is the brand's most versatile jacket. It can be used for an outing in early spring or for a ride in the middle of winter if you add a thermal undergarment underneath. Stretchy, comfortable, breathable, and windproof, the Go W Jacket will be ideal in many situations. Additionally, the reflective elements of the Go W Jacket will help keep you visible during your rides in low light conditions.