This UV50+ quarter zip base layer is designed to help regulate your body temperature, whether you're running, riding, or walking the dog. It features ventilated underarms to keep you cool and dry. The fabric is sweat-wicking, antimicrobial, and offers 360-degree stretch for unrestricted comfort. Silky-smooth fabric, ultra-soft seams, and flat-lock stitching minimize chafing and bulk when worn under other layers. This base layer is designed to coordinate with popular LeMieux colours for accessories like hat silks, saddle cushions, and fly hoods.