ASTRO PNEUMATIC Die Grinder Combo Kit withBurrs AO1221 Blue Composite Body 1/4" 90?? Angle Die Grinder - 20,000RPM - Front Exhaust & Composite Body 1/4" Mini Die Grinder - 25,000rpm - Front Exhaust & 8pc. Double Cut Carbuye Rotary Burr Set 1/4" Shank Features Model 1240 Composite handle reduces vibration Rib textured handle provides a firm grip Lever throttle for feathering control Compact and lightweight Front exhaust Built-in regulator Features Model 1205 Composite handle reduces vibration Rib textured handle provides a firm grip Lever throttle for feathering control Front exhaust Built-in regulator Features Model 2181 SA-5: Cylindrical shape 1/2" X 1", SA-3: Cylindrical shape 3/8" X 3/4", SC-3: Cylindrical radius end 3/8" X 3/4", SC-1: Cylindrical radius end 1/4" X 5/8", SD-1: Ball shape 1/4", SD-3: Ball shape 3/8", SF-3: Tree shaped radius end 3/8" X 3/4", SF-5: Tree shaped radius end 1/2" X 1" Should not exceed maximum 30000rpm, All above burrs are 1/4" shank, USA standard