STAY COOL WICKING, ULTRA-BREATHABLE, FLATLOCK SEAMS FOR COMFORT, AND REFLECTIVE DETAILS. 4-OUNCE 100 PERCENT POLY JERSEY WITH STAY-COOL WICKING TECHNOLOGY, SELF-FABRIC COLLAR, REFLECTIVE O HEAT TRANSFER AT BACK NECK, AND OGIO® ENDURANCE HEAT TRANSFER LABEL FOR TAG-FREE COMFORT. FEATURES SET-IN SLEEVES, REFLECTIVE STACKED O HEAT TRANSFERS AT SLEEVES, AND REFLECTIVE O ENDURANCE HEAT TRANSFER AT BACK LEFT HEM.