Efficient BL Brushless motor is electronically controlled to optimize battery energy use for up to 50% longer run time per charge The BL Brushless Motor eliminates carbon brushes, enabling the BL Motor to run cooler and more efficiently for longer life The electronically-controlled BL Brushless Motor efficiently uses energy to match torque and RPM to the changing demands of the application Variable 2-speed 1/2" Hammer Driver-Drill (0-550 & 0-2,100 RPM) (0-8,250 & 0-31,500 BPM) delivers 1,250 in.lbs. of Max Torque; weighs only 6.0 lbs. with battery Impact Driver features 3-speed power selection switch (0-1,100 / 0-2,100 / 0-3,600 RPM & 0-1,100 / 0-2,600 / 0-3,800 IPM) provides 1,550 in.lbs. of Max Torque; weighs only 3.3 lbs. with battery