1/4" Medium Die Grinder - 22,000rpm - Rear Exhaust Rear exhaust air flow system directs air away from work surface Compact and lightweight Built-in regulator Safety lever 1/4" 90° Angle Die Grinder - 20,000RPM - Rear Exhaust Composite handle reduces vibration Rib textured handle provides a firm grip Lever throttle for feathering control Compact and lightweight Rear exhaust Built-in regulator .