The I/O was one of the original goggles with a quick-changing lens and remains in the market because of its rock solid design. The medium/large fitting frame houses a quick-realeasing, spherical lens with anti fog coating and a Porex filter to further eliminate fog. The strap is dual adjustable, with a clip in the back for easy on/off and each frame comes with two lenses to battle any lighting condition. This year you can choose from 16 different colorways to compliment any style.