Bafang supplied set of 1/2 inch drive M33 sockets specifically designed to tighten the lock rings of the mid drive BBS02 and BBSHD motors. There are two sockets, one designed for the inner lock ring with 4 notches, and a second designed for the outer lock ring with sixteen notches. Complaints about motors loosening are usually attributed to the M33 lock rings NOT being tightened well enough, but with help from these sockets you will be able to tighten the lock rings properly. Tip: place bike wheels on the ground and have a partner hold the brakes when tightening down the lock rings for best results, motor should be pressed upward against frame, this is how the motor counters torque. Tightening the lock rings properly holds the motor upward in the correct position. Sold individually or as a pair (save 5$ when bought as a pair).