JSP® 5" jewelers engraving block ball features a rubber base allows you to have a secure and hands-free grip on your piece while engraving. Small, maneuverable size. Clamps are secure but smooth to work with while your two hands. Included pins and nylon plates to avoid marring the piece. Great for hand engraving, stone setting, jewelry repair, model making, and other precision work. Product features: small solid work support dimensions: 5" x 5" x 5" pins length: 0.79", width: 0.17" special T-wrench length: 7.5", width: 7.5"