The STEELMAN Micro Die Grinder is the perfect tool for cleaning and polishing engines in addition to porting and deburring castings. It has an easy 'Twist throttle' design that leaves you in control. The piped away rear exhaust leaves your work untouched, with less chance of debris in the air around you. This Micro Die Grinder also comes equipped with precision ball bearings. The Spec's are as follows: 54,000 RPM, 1/8 Inch collet size, 1/8 Inch NPT air inlet thread, 5 millimeter air hose ID, 90 PSI air pressure, 4 CFM, overall length 5.25 Inch and weighs 0.75 pounds.