For those searching for a lightweight yet extremely warm jacket for the cold-weather riding season look no further than the Castelli Fly Thermal Jacket. This zip-up jacket features a FLY SL Shell that offers superior rain and wind protection a GORE-TEX INFINIUM WINDSTOPPER inner lining for breathability and CLIMA SL Insulation for unmatched warmth. Three rear open pockets and a zippered security pocket store our ride essentials while the elastic and silicone at the waist keep our jacket in place as we ride through the winter.