Labyrinth construction seals and protects the drive gear and bearings from contamination for longer tool life. Lock-on/off feature for continuous operation. AC/DC switch for use with alternative power source. Protective zig-zig varnish seals the armature from dust and debris for longer tool life. Extra large paddle switch for comfortable operation. Thicker coil wires are wound more closely to reduce heat and energy loss. All-ball bearing design and metal gear housing for durability. Push button spindle lock for operator convenience. Includes grinding wheel, wrench, side handle, flange, and wheel guard.