anyone use these on their motors? if so what model?

also what is the first thing you would use this to test on used motor(s) purchases to verify things are in order etc? Thanks

TRINITY MOTOLYSER ANY GOOD

eh, you can't exactly pick and choose motors unless your on a team but prob best option is to find someone who has the box (some tracks) with the ir measuring (very expensive) and try to find a motor with the lowest ir without being illegal.