Kickback brake engages when a pinch, stall, or bind-up event is sensed, Flexible - power of corded. Freedom of cordless. The world's first battery that automatically changes voltage when you change tools., E-clutch activates in less than a tenth of a second when a pinch/stall is detected, shutting down the motor, 9,000 RPM speed allows the use of 4-1/2" to 6" wheels, Brake engages when trigger is released, stopping speeds of 1.5 seconds with standard grinding wheel (0 cm)