Pins size: 10 mm in diameter, 9 mm in length; : PVC; Rubber pin keeper size: 10.6 mm in diameter, 7.6 mm in height. Practical shape: protruding half round shape handle on the pin back is designed for easy grasp, thus you can be convenient to take on. Tight 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 for tie pin. Multiple purpose: good for jewelry making; You also can use tie back to fix object, such as photos, fabrics, cloth, map, scrapbook, . Replacement for the lost pin back: can be the pin clutch backs, fits for all lapel pins, tie tacks, service and jewelry.