110V Vibro-Graver This rugged industrial quality engraving tool makers permanent markings on the hardest steel, glass, plastic, stone, wood, or almost any surface. Used extensively by jewelers to make background effects on jewelry. Features a durable, tungsten carbide engraving tip, positive on-off switch, and spark-free motor that vibrates at 7200 strokes per minute. The adjustment dial changes length of stoke and depth of mark.