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: 6.5mm dia x 36mm long
D: Lock nut:M6 x 17mm (10mm threaded.)
Weight: 35g per axle incl. nuts