Pins size: 10 mm in diameter, 9 mm in length; Material: PVC rubber and nickel plated brass; Rubber pin keeper size: 10.6 mm in diameter, 7.6 mm in heightPractical shape: protruding half round shape handle on the pin back is designed for easy grasp, thus you can be convenient to take onTight rubber pin back: the PVC pin back is tight and they are not easy to fall off; Each pin back has a hole which is compatible with the tie tack pinMultiple purpose: good for jewelry making; You also can use the tie back to fix object, such as photos, fabrics, cloth, map, scrapbook, etc.Replacement for the lost pin back: can be the pin clutch backs, fits for all lapel pins, tie tacks, citation bars, service bars and jewelry Note: The data are all measured manually, please allow 1-3cm error, due to the difference in light and display, there will be a certain color difference, the actual object received shall prevail.