Bolle Tracker II goggles are a clear lens eye protection of a high standard as with all bolle products. Incredibly lightweight at only 52g. With Bolle's patented anti-fog and anti-scratch lenses. Like with most goggles they will still fog up if you perspire. But using additional anti-fog will minimize fogging. Held in place by a comfortable and adjustable 20mm elasticated nylon non slip strap. The Polycarbonate frame has side ventilation at the ends of the lenses. The 2.2mm lenses are also ballistically tested, so they easily meet the requirements of airsofters and meets specification for EN 166 - Permanent Wear and EN 166 - Impact at extreme temperature (-5 / +50*C). The goggles come with a microfiber pouch to keep your goggles safe. The Tracker ll;s can also accept an optical insert for prescription glasses wearers.