RANDOM ORBIT, ACTION. Researched and Developed for Ultra-Fine Finishing. Custom handle option (handle is optional and not included with sander) guarantees proficient control at any angle. Flex-cover gives comfortable grip, prevents stiff fingers. Low Profile, vibration free motor insures full contact sanding. Unique Air Efficiency System. Positive-Action Drive supported by 4-special bearings generates more power on less air. Over-size Drive Head eliminates pad-wobble for full contact Sanding.