The set includes cylindrical and conical grinding head ( 6.35mm standard shank) designed for quick drill removal in tight spaces These electric drill sharpening head minimize while maintaining consistent grinding efficiency polish metal surfaces, refine wood edges, or restoring ceramic / glass items using these rotary grinding stones in workshops or home garages Ideal for metalworkers, woodcrafters, and enthusiasts needing mounted grinding points for jewelry making, tool maintenance, or finishing projects Upgraded your rotary tool with 2pcs brown corundum grinding stones featuring 1 / 4inch hexagonal shank, perfect for sharpening, carving, and polishing, Manufacturer: GinMimi