Features: Great for opening and closing screw back case, especially for Rolex oyster model. Including a wrench and six grooved dies of different diameters. Adopting premium steel material with stable construction, it is rustless and durable. Easy and handy to take with you because its small size and light weight. It comes with a storage box for easy storage and well organization. Size of grooved chucks: NO.1--18.50mm / 0.73inch NO.2--20.20mm / 0.8inch NO.3--22.50mm / 0.89inch NO.4--26.50mm / 1inch NO.5--28.30mm / 1.11inch NO.6--29.50mm / 1.16inch Weight: 367g Package included: 1 X Wrench 6 X size of grooved chucks(rings) Specification: Material: Steel Color: Silver Item Model: 5537 Wrench Size: 20 * 1.6cm / 7.87 * 0.63inch Type: Watch Repair Tools & Kits 6 SIZE OF GROOVED CHUCKS: NO.1--18.50mm NO.2--20.20mm NO.3--22.50mm NO.4--26.50mm NO.5--28.30mm NO.6--29.50mm User friendly design You can repair your watch or change the batteries easily with this professional watch tool. Great for opening and closing waterproof & grooved watch back case. -Suit for ROLEX/TUDOR/OTHER