The Hercules prescription impact glasses/goggles comes with both a pair of arms and a goggle strap. The prescription lenses are made from high pressure injected polycarbonate. They have asoft Hypo-allergenic silicone lining to absorb front or temple impacts. The frame is vented to prevent misting. Choose either the fully adjustable elastic headband our wear them with the supplied arms as a pair of glasses. The frame is designed to comply with CE approval for ball impact tests ASTM, BS 7930-1:1998 and USRA and ASTM F803 standards for racket and impact sports, ideal for football.