Castelli pro issue sleeveless base layercastellis 3d mesh fabric creates dead air space next to your skin while the polyester capillary action moves sweat away features 100 polyester 3d mesh fabric reduced seaming at shoulders for extra comfort wider collar to fit under aero jerseys flat waist hem to lie flat in shorts 15 25c59 77f weight 44g largebuy castelli clothing from chain reaction cycles the worlds largest online bike store