The Watch Repair Tools Kit is a must-have f any watch enthusiast professional. It includes a universal wrench f opening closing watch back cases, as well as a key f waterproof watch cases. The key comes with 4 sets of clamps: Round, Flat, Square, Toothed, ensuring compatibility with a wide range of watch cases. This tool is specially designed f opening closing screw-in back cover watches. It is easy to use easy to carry, making it convenient f on-the-go repairs. The largest open table diameter is 3.70 cm, providing ample space f most watch backs. The kit includes 18 pieces, ensuring you have all the tools you need f watch repair. Made from high-quality steel, the Watch Repair Tools Kit is durable long-lasting. It features a small three-jaw opener with 6 groups of 3 steel teeth, totaling 18 teeth. This allows f precise secure opening of watch back covers. The tool is fully adjustable via a thumb wheel, making it easy to customize f different watch sizes. It can open watch backs ranging from 17mm to 37mm in diameter. To use the tool, simply adjust the three steel teeth to the appropriate location choose the bayonet shape that matches your watch's back cover. Place the tool on the back cover bracket apply pressure while rotating it to the left. This will open the bottom cover allow f easy access to the watch's internals. The Watch Repair Tools Kit includes 1 x Watch Back Case Opener Wrench Tool Kit Set 1 x Blue Stage Case f convenient stage transptation. Key Features: Universal wrench f watch back case opening closing Key f waterproof watch case with 4 sets of clamps Special movable screw-plug back cover tool Largest open table diameter of 3.70 cm 18-piece kit f comprehensive watch repair Made from high-quality steel Opens watch backs from 17mm to 37mm Fully adjustable via thumb wheel