Built to adapt to your ever-changing environment, the WX Valor provides exceptional protection and visibility in any conditions. Wiley X ANSI-rated, OSHA approved frames and lenses must withstand the impact of a .25" diameter steel ball traveling at 150 feet per second. This model is also tested to VO Ballistics which consists of a frame and lens being impacted with a .15 caliber projectile traveling between 640-660 feet per second per Mil-Standard MIL-PRF-32432(GL) . This test is meant to simulate shrapnel that may be encountered on the battlefield. Fits most headsizes.