Pearl Izumi Men's Elite Inrcool Tri Sleeveless Jersey Main Body: 63% nylon 22% elastane 15% polyester Back: 80% polyester,20% elastane Imported ELITE Transfer In-R-Cool fabric powered by coldblack&reg; provides superior cooling and reflective sun protection Elite Transfer In-R-Cool fabric features Lycra Sport that helps garments maintain original compression levels ELITE Transfer Aero fabric is strategically placed for superior aerodynamics A clothing system that works to help you maintain the perfect temperature for the weather conditions and activity range day in and day out