WX Gravity is a classic wrap around design that is made for style, comfort, and safety. Removable gasket included for added safety and protection. "WX" logo featured on the temple. Meets or exceeds military ballistic standards. WX Echo is RX ready for those who need prescription sunglasses. Smoke Grey lens technology is excellent in extra bright conditions but won't distort colors; it also provides maximum glare protection. LA™ Smoke Grey Lens technology darkens as the sun brightens and offers maximum optical clarity.