Quick-Shift Mode uses the brushless motor’s electronic controls to find the best balance of speed and torque for each application for more efficient fastening Makita-built brushless motor delivers 3,600 Max RPM and 1,590 in.lbs. of Max Torque 4-speed power selection (0-1,100/ 0-2,100/ 0-3,200/ 0-3,600 RPM & 0-1,100/ 0-2,600/ 0-3,600/ 0-3,800 IPM) provides precise fastening control for a wide range of applications Additional one-touch 4-speed power selector button under the chuck for added convenience Assist Mode (A-mode) feature helps eliminate "screw cam-out" and "cross threading" by driving at low speed until tightening begins