This smartphone/tablet holder features a length-adjustable design that securely attaches to the center of the headrest. The arm extends up to 85.5cm, and by opening the buckles on both sides, you can enjoy the optimal viewing angle anywhere in the back seat space. It remains stable even when the car is driving on bumpy roads. Clamp length: 13.5cm-27cm. Compatible with devices from 4.7 to 12.9 inches. Used for about a year. There are some scratches on the arm, but it functions perfectly.