Features and Benefits: 202 - composite body 1/4" medium die grinder - 22,000rpm - rear exhaust; Rear exhaust air flow system directs air away from work surface; 2181- 8 piece double cut carbide rotary burr set; 1/4" shank in blow molded case; The Astro 2181B kit includes the Astro 202 die grinder and the Astro 2181B rotary burr set.