Watch Back Case Opener Sticky Friction Ball Screw Remover Screwball Rubber Ball Watchmaker Tool Practical Rubber Screwing Ball Description: Watch Back Case Opener: Opening watch case backs with ease using this friction ball. Easy to Use: Hold the watch in hand and in the other hand, press the friction ball onto the back of the watch. Start twisting to unscrew the watch back. Diameter: 2.95 inches in diameter(75mm). Upgraded: It will never scratch or damage your watch, will not leave marks. Watch Repair Tool: This is a watch repair tool, not a toy ball, only use to open the screw thread back watchcase. Specification: Material: Rubber Size Chart: 7.5cm/2.95inch Package Includes: 1Watch Back Case Opener Ball Note: Please allow slightly errors due to manual measurement and different monitors. _x000D_