New style Pilot RC Axles designed with a machined shoulder and nyloc nut so there is no need for collars.
Sold as a pair
A: Thread: 8mm dia x 17mm long
B: Shoulder (including hex) 9mm dia x 21mm long
C: Axle shaft: 6mm dia x 30mm long
D: Lock nut:M5 x 7mm
Weight: 29g per axle incl. nuts