Chicago Pneumatic 854 4" Heavy Duty Air Grinder. Aluminum alloy housing is rugged yet lightweight for maximum operator comfort. Spiral bevel gearing in angle head provides extended life and smooth low vibration. Powerful .6 hp high performance motor for fast, efficient grinding in tight quarters. Removable dead handle allows access to tight quarter work. Applications - weld preparation and smoothing, rust removal, deburring and blending of steel, cast iron, and aluminum. Free speed - 12000 rpm. Specifications: collet/spindle size - 3/8"-24 spindle, wheel size - 4", cfm - 6, hose size - 3/8", free speed - 12000.