STAY-COOL WICKINGULTRA-BREATHABLEFLATLOCK SEAMS FOR COMFORTREFLECTIVE DETAILS 4-ounce 100% poly jersey body with stay-cool wicking technology 4.1-ounce 100% poly mesh shoulder and back panels Self-fabric neck Reflective stacked O heat transfers at back OGIO Endurance heat transfer label for tag-free comfort Reflective O Endurance heat transfer at back left hem Reflective O heat transfer at front left hem