If you have a DIY Bafang e-bike, you may have to undo or tighten the lock ring securing the motor to the bottom bracket. The Bafang tool is woefully inadequate, and although steel sockets are available, they are expensive.

This is a highly functional socket which I designed and printed in PETG, easy to use a ½" torque wrench with, with notching inside to secure the tool. Tested up to rated torque spec 25-30Nm, note this is not the tool for the inner ring which I have not designed, printed or tested yet as I do have the steel version of that.

Mine is printed in a combination of green and black since my black filament ran out prior to completion, gives it some nice flare though.

Can be printed with 0.6mm nozzle like I did, or 0.4mm nozzle for which you will probably need to adjust layer height and thickness.