Super-lightweight construction with just enough warmth and protection Low/no collar for temperature regulation Castelli FLY Fabric Technologies: FFT GORE-TEX INFINIUM WINDSTOPPER inner lining CLIMA SL Insulation for extra warmth FLY SL Shell for wind and rain protection 100% recycled post-consumer outer shell and lining Top and bottom-opening YKK Vislon zipper 3 back pockets with zippered security pocket for valuables Elastic and silicone at waist to keep vest in place Reflectivity at waist Weight 99 g (M) 10-18°C / 50-64°F