STAY-COOL WICKINGSTRETCHFLATLOCK SEAMS FOR COMFORTREFLECTIVE DETAILS 5.2-ounce, 88/12 poly/spandex with stay-cool wicking technology OGIO heat transfer label for tag-free comfort Elastic locker loop on center back neck Black reflective O Endurance heat transfer bar on back right shoulder Thumbholes for warmth Black reflective O heat transfer on front left hem