After exposure to the sun, sunglasses become more handsome! The working principle of color changing lenses is that when exposed to ultraviolet light, the color changing coating on the lens gradually darkens. The speed of color changing is directly related to the depth and the amount of ultraviolet light encountered. The stronger the ultraviolet light, the faster the color changing speed. The faster the color, the darker the color, and vice . The slower the speed, the lighter the color. The darkest color changing lens can reduce 80%. Helmets that can change color to 50-80% less light in strong sunlight for up to 30-40 seconds. In the absence of sunlight, the color of the lens gradually becomes lighter, and it takes about to reduce the light transmission from 80% to 50%. It is necessary to achieve 30% light transmission before color change, and a completely 0UV environment is required, such as at night.<br><br>Only compatible with for X15 RF-1400 Z8 Z-8 -F2 RF1400 NXR2 helmets Colour:As Shown Material:plastic<br><br>Package Contents: 1 x Helmet Photochromic Visor<br><br>Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.