Watch Back Case Cover Opener Remover Wrench Dies Repairer Tool Set for Rolex Oyster 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. Specification:  Material: Steel Color: Silver Item Model: 5537 Wrench Size: 20 * 1.6cm / 7.87 * 0.63inch Diameter of Dies: Approx.  18.50mm / 0.73inch 20.20mm / 0.8inch 22.50mm / 0.89inch 26.50mm / 1inch 28.30mm / 1.11inch 29.50mm / 1.16inch Weight: 367g Type: Watch Repair Tools & Kits Package List: 1 x Wrench 6 x Dies Note:Before buying, measure the size of the back cover of your watch to see if it matches the six molds 18.50mm, 20.20mm, 22.50mm, 26.50mm, 28.30mm, 29.50mm, and the size is the same before you can buy.