1. Material: rubber
2. Product use: for threaded watch back cover
3. Usage: the ball presses against the watch back cover, rotate it to open it
4. Comfortable hand feeling, easy to change battery at home
5. No trace to open the cover, no damage to the watch
6. Diameter: 70mm
7. Weight: 45g
Note: delivery only rubber ball, does not include other items in the picture