Tough And Built To Last, This Polished Hardened Alloy Steel Cube-shaped Dapping Block Has 12 Half Spheres (from 4 - 40mm); 5 Cylinder-grooves And 5 "v" Shaped Linear Grooves. Cube Edge Measures About 2".* 2" Square Cube * 15 Round Cavity 4 to 14,16,18,20 & 25mm * 6 Rectangle, 5-U & 6-V-Shape Groove * Grinding/Polished Harden Steel * Cube weight: 1.95 Lbs.