Description: Material:ABS Size:25.4 * 20.3cm Light transmission rate: < 92% Focal length: -330mm Increase the angle of view: 0-28 degrees on the left and right, 0-18 degrees on the bottom Conversion: 1inch=2.54cm, 1cm=0.393inches Scope of application:Reverse sticker is suitable for two cars, there is the rear of the car can not, the straighter the effect of the rear glass hanging the better. In the rear outside the back of the spare tire, and the upper edge of the spare tire beyond the rear window bottom line of the off-road vehicles, because the spare tire blocked the effective line of sight, are not suitable for the use of reverse stickers. Features: With synthetic rubber material, it is easy and convenient to use Stickers on your rear window and gives a much wider view of the road behind you with no blind spots. Enables you to spot children and pets that are below the level of the rear windo Quality lens provides low distortion and no dazzle or double images Easily removable - sticks to your window with water - it's that simple! A wide r ear view Fresnel lens is THE sensible option for any vehicle owner - get yours now and increase Easily applied and removed by using water only. Easy installation on rear window of your vehicle No tools required. Need no adhesive, just use water only The lens is better working for vertical rear windows How to install? 1.Installed in the window below effect is better. 2.Make sure the installation position of the glass surface is clean,then wet it with water. 3.The product smooth surface paste on glass wet area. 4.With a soft towel remove paste surface bubbles . 5.Paste surface after drying can be adsorbed on its own and can not fall off. Warm Tip : Please be reminded that due lighting effects, monitor's brightness/contrast settings etc, there could be some slight differences in the colour tone of the website's photo and the actual item. Item Measure by hand, it could be 1cm different,your kind understanding will be much appreciated.