This is a Electric saw chain sharpener: 12-volt grinder comes with a car power adapter and alligator clips. Sharpens most chainsaw chains up to .404-inch pitch. Sharpening stones inside: Contains 3/16 Inch (4.8 mm), 5/32 Inch (4.0 mm) 11/64 Inch (4.5 mm) and 7/32 Inch (5.5 mm) grinding stones.Easy chainsaw sharpening kit: Simple sharpening angle adjustment guide for accuracy. Lightweight: Ergonomic design. Long power cord included (5 meters)Powerful motor: Runs at an optimum 25,000 RPM