Nylock Nuts, M10x1.0

Nylon lock nuts provide much more resistance to loosening from motor vibrations and axle wiggle caused form regenerative braking than regular nuts or nuts with split lock washers.   

M10 nuts are used on earlier versions of the GMAC motor and the small SAW20 Brompton folding bike motor. Be aware that the Bafang G310/G311 and most other small hub motors that appear to use a 10mm axle actually use the original 3/8" x 26 TPI bicycle standard. These are not compatible and will bind.