From the Manufacturer The Astro Pneumatic T20AH 1/4-Inch 90 Degree Angle Die Grinder with Safety Lever is designed for heavy duty grinding, casting cleaning, and weld smothering. It can be used with carbide burrs or mounted points. Wide range of functionality includes mechanic and body shops, fabrication shops, shipyards, foundries and industrial plants. Specifications: Collet Size: 1/4-inch, Free Speed: 20,000rpm, Overall Length: 5-inch (127mm), Net Weight: 13/16-pound (.31kg), Motor: 1/3hp, Air Inlet Thread NPT: 1/4-inch, Air Hose I.D. Size: 3/8-inch (10mm), Avg. Air Consumption.: 3cfm, Sound Pressure: 89 db(A), Sound Power: 100.8 db(A), Vibration Level: less than 2-1/2 m/s2, Air Pressure: 90-120psi.