Condition: 100% Brand New Item Type: Watch Gaskets Material: Rubber Optional Thickness: 0.5mm, 0.6mm, 0.7mm Usage: Installed on the watch back cover, sealing the back cover, prevent water and dust Color: Black O Ring Diameter: (unit MM) 0.5, 0.6MM:12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30. 0.7MM: 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30. Package List 750 x Watch Gaskets 1Rubber gasket set, is installed on the watch back cover, sealing the back cover, prevent water and dust. 2Different sizes can meet your different repairing and maintenance needs. 3Suitable for watchmakers and watch repairing workers to use. 4Made of quality rubber material, good sealing effect and high elastic. 5Excellent replacement part for almost all kinds of watches, widely application.