Writes like a pencil on any material. Marks permanently on any surface from hardened steel to glass. High-speed, reciprocating motor delivers 7200 strokes per minute. Calibrated stroke adjustment dial regulates length of stroke, depth of engraving from fine lines to deep marks. Pencil-grip for precise control; durable nylon housing with handy hanger. Solid carbide point practically wearproof. 115V, 60Hz AC only.