Made of high hardness ceramics, durable and not easily broken. Suitable for grinding and polishing of metal inner surfaces, welding points, welds, or burrs. Easy to install, good heat dissipation, no need to disassemble for polishing, saving time and effort, effectively improving work efficiency. The diameter of the grinding head is about 4 millimeters, the length is 19 millimeters, the diameter of the handle is 3 millimeters, and the total length is about 41.5 millimeters. Please confirm the size before purchasing. There are 20 pieces in one package., Weight: 0.1322773572 pounds, Manufacturer: Young Wolf