STAY-COOL WICKINGULTRA-BREATHABLEFLATLOCK SEAMS FOR COMFORTREFLECTIVE DETAILS 4-ounce 100% poly jersey with stay-cool wicking technology Self-fabric collar Reflective O heat transfer at back neck OGIO Endurance heat transfer label for tag-free comfort Set-in sleeves Reflective stacked O heat transfers at sleeves Thumbholes for warmth Reflective O Endurance heat transfer at back right panel Reflective O heat transfer at left hem