13 Amp Equivalent Power* Kickback Brake engages when a pinch, stall, or bind-up event is sensed and the electronic brake engages with maximum force to quickly stop the wheel, reduce the movement of the grinder, and shut the grinder off. Allows for up to 6 in. wheel size for both cutting and grinding applications. Anti-Rotation E-CLUTCH® System 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 up to 6 in. wheels Maximum initial battery voltage (measured without a workload) is 20 and 60 volts. Nominal voltage is 18 and 54. Brake engages when trigger is released, stopping speeds of 1.5 seconds with standard grinding wheel (4-1/2 in. x 1/4 in. Bonded abrasive wheel, non-hubbed) Spindle Size:5/8-11 in