The castelli passo giau jacket has been created with a great style and has been designed with a sophisticated body mapping which brings the right fabrics to each part of your body this means the windstopper fabric on the chest is thicker while being lighter on the body and arms and castelli39s own warmer material on the back of the jacket provides excellent breathability this castelli cycling jacket is ideal for cold days when you plan on riding hard or a less energetic ride on a mild day