Master Mechanic 1202S1115 Straight Die Grinder Kit with Aluminum Housing, 1/4"Great for high speed grinding, porting smoothing, general polishing and deburring. Features Sealed ball bearing construction for durability and Heavy duty aluminum housing comfort grip. Includes 10 grinding stones, 2 wrenches, nipple, 1 4" collet & carrying case. 1 4" Great for high speed grinding, porting smoothing, general polishing and deburring 2500 RPM variable speed 1 4" collet Sealed ball bearing construction for durability Heavy duty aluminum