S T A Y- C O O L W I C K I N G U L T R A B R E A T H A B L E F L A T L O C K S E A M S F O R C O M F O R T R E F L E C T I V E D E T A I L S 4-ounce 100% poly with stay-cool wicking technology O G I O heat transfer label for tag-free comfort Reflective O heat transfer on left hem Reflective O Endurance vertical bar heat transfer on center back