Perfect for any toolkit whether you're a professional watchmaker or a hobbyist.Note: The color of this product is shipped randomly Hold the watch in one hand and in the other hand, the friction ball onto the back of the watch. Start twisting to unscrew the watch back. Watch Repair Kit, makes you open the watch in an easy, precise, and safe way for any but the most difficult waterproof casebacks. Easy to use, simply squeeze, , then turn. You can fill air by the basketball pump yourself if need full air Colour:Random Color (Note: the color is random, no designation is accepted) Material:rubber Package Contents: 4 * Watch Case Open Ball Only the above package content, other products are not included. Note: Light reflection 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.