For extreme sport enthusiasts who are tired of changing lenses from clear to smoke. Put the sun to work for you! Birdz Eagle Photochromic lenses darken in the UV rays of the sun. The Eagle goggle is equipped with soft airy foam padding for a comfort fit. In addition to being antifog, the Eagle's high quality shatterproof polycarbonate lenses provide maximum protection from the elements. The quality UV400 shatterproof lenses eliminate the harmful sun's rays. Shatterproof polycarbonate lenses provide maximum eye protection. One size fits most.