The Nathan Photon Vest is made with soft, lightweight, breathable mesh. Zippered front pocket with elastic band keeps smart phones and valuables secure. Hidden key pocket. Up to 1,200-foot visibility. Removable L.E.D. strips on front with three light settings for up to 150 hours of illumination. Replaceable battery. 360 reflectivity. Adjustable fit. Sz: One size fits most.