Clear Inside. Dark Outside. One Ounce Either Way. SunShift goes clear to smoke in seconds, on a frame light enough that you forget it's on your face. Our Advanced Light Technology (ALT) reacts to UV , not brightness. They will not transition under indoor lighting or in vehicles with UV-treated windows. Why it's great for shooting: Tinted enough to kill glare, deliberately not dark enough to lose your front sight or wash out target definition in shadow. What's the fit: SunShift's nose piece sits higher and wider to keep the lens off your cheeks, making it great for a universal fit. What it's rated: Independently tested to ANSI Z87.1 impact standards. What it does in heat: FogGuard Pro™ is bonded into the lens so you can say goodbye to steamy range days. What's the frame: 1 oz total with our lightest TR90 thermoplastic nylon frame. How Dark Does It Actually Get? Photochromic lenses are categorized from 0 (clear lens) to 4 (very dark tint for exceptional glare). SunShift was designed to go from category 0 to category 3. We chose this so the lenses never go so dark that clarity on sight or target is lost. Darkening takes seconds. Clearing takes a couple of minutes. That's true of every photochromic lens, ours included. Which SunShift Should I Get? If you shoot exclusively outdoors in bright sun and want the darkest possible lens, the SunShift Polarized is the better & more affordable buy. If you move between indoor and outdoor, or shoot at dusk, this is the pair.