1、NEED TO INFLATE BY YOURSELF: Due to the need for transportation, the watch friction ball needs to be deflated and then packed, so you need to inflate the ball yourself before use(the ball needs to be inflated to a semi rigid state, not too full), this is very important 2、WEAR RESISTANT MATERIAL: Watch case opener ball is made of excellent rubber material, and open the back cover by friction with the back cover of the watch 3、EASY TO USE: You only need to fix the watch on the repair bracket or hold firmly in the hand, and then squeeze the ball to cause friction between the ball and the back case, Rotate the ball toward the open direction of the watch case 4、SCRATCH PREVENTION: This is an innovative tool that allow you to easily, accurately, and safely open the watch on the back of any waterproof case. The smart design make it fit and grip the watch evenly, giving it more power but never scratching your watch 5、SAFE DISASSEMBLY: Squeeze, press, rotate, the watch case open ball can be evenly and firmly fitted to the surface of various watch sizes, allowing you to remove the back safely and efficiently Item Type: Watch Cover Opener Ball Material: Rubber Quantity: 1 Piece Diameter: Approx. 70mm / 2.76in 1 x Watch Cover Opener Ball