Smarteer Tempered Glass Screen Protector with Smart Invisible Return Key & Confirm Key for iPhone 6S A built-in special circuit connects the lower left corner and lower right corner with the top left corner and top right corner of the screen, where are the positions of most IOS APPs for Back Button and Confirm Button; Without installing any software application, a dedicated physical [Return Key] is designed to be the easy way of going back to the previous screen; and a [Confirm Key] is designed to use the function on the top right corner in most APPs A smart screen protector makes the device easier to use with a single hand, and decreases the chances of breaking your screen when your cell phone drops by 99% Made of premium 9H ballistic nano ultra clear tempered glass: anti-scratch and ultra-clear with high sensitivity touch; the back button itself is invisible, and nothing change in the outlook