Castelli womens pro issue sleevelessthe castelli pro issue sleeveless baselayer is the piece the pros requested for those in between conditions youre not looking for warmth from your base layer just something to move the moisture away from your body and help your race jersey perform featuresmaterial 93 polyester 7 elastane100 polyester 3d mesh fabricreduced seaming at the shoulders for extra comfortcollar is wider for better aesthetics under an aero jerseyflat waist hem sits better und