Makita Angle Grinder 9566CVR 6 Inch 13 Amp (4000 to 10000 RPM SJS Clutch Variable Speed Metal Cutting Shaping Fabrication Disc Unit) Chippers Dual Mechanical Shaft Seals: Premium Dual Mechanical Shaft Seals: Premium silicone carbide seals run in an isolated oil chamber to prevent fluid ingress into the motor armature 200 RPM maximum operational velocity this heavy duty grinder integrates an SJS™ mechanical clutch system that disengages gears if the wheel binds to protect internal components Constant Speed Control Technology: Automatically applies additional electrical power to the motor under heavy loads to maintain RPM consistency