.12 to .18 Crankshaft Axle Lock Nut
 
To suit 5mm crank shaft/axles
 
Item is 19mm long end to end (smooth part is 9mm)
This is the shorter one we stock, longer ones available.
 
Suitable for most 1.10 scale models
 
Features a slot for an e-clip (7mm) and 3mm thread hole at the other end