I'm new to industrial sewing machines and the clutch motor was a little terrifying. With this motor I can easily control the speed. The low limit is 100rpm and with the 75mm pulley that comes installed on the motor is plenty slow enough for consistent back stitching. It also comes with a 50mm pulley if you need it even slower. The instructions could be better but I didn't have too much trouble getting it all installed. The needle positioner is great. You can set it to stop needle up or down. And pressing the foot pedal backwards turns the machine another 1/2 turn. What I mean is if I have it set to stop needle down, pressing the foot pedal backwards lifts the needle. Keep in mind you might need a new belt with this motor. I needed to get one a few inches shorter. I installed this on a juki dln 415.