Worn by fire and rescue, military, and industrial workers. Designed for freedom and protection during sports and field work. Can be worn underneath your military gas mask. Non-reflective and contoured to match facial features for comfort. Self-adjusting straps hold frame securely on face. Made of DuPont nylon. Meets ANSI Z87.1 standards and OSHA requirements. Accepts prescription lenses (not included). If the size is not imprinted on the inside of your prescription glasses, see your optometrist for correct size.