It is a back button for . Paddles handle extended button, you can customize the mapping of the button function on the back, support the TURBO burst function, plug and play, and bring users a different gaming experience. 1.Suitable For . 2. quality. 3.Improve the flexibility of operation and enhance your gaming experience. Function Setting: 1. Long the SET button for 2 seconds, x light flashes quickly. 2. the M1 or M2 ( Pressonce to switch once ) ,lights flashing slowly 1n sequence ( FlashingSequence: x- o - △ - 口 - R3- L3- R2- L2- R1- L1 ) 3. When the target button is flashing, the SET button,finish setting. Clear Cache: Long the SET button for 5 seconds, the LED changes from blinking to off Memory Function: Insert the handle again and still retain the last programming function.The factory default has no definition. Turbo function: the M1/2 and Turbo at the same time, the function key has Turbo continuous launch function .Repeat this step to cancel Colour: black Material: ABS Size: 99.5 x 57MM Package Contents: 1 x For Joysticks Rear Button Only the above package content, other products are not included. Note: Light 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.