This axle starts life as an official B.S.A. Pinewood Derby axle. It is C.N.C. machined true and round, Derby Worx then adds 4 grooves (1 behind the axle head and 3 in the hub contact area) to reduce friction and hold graphite then head is back-cut for further friction reduction at the hub face on the wheel. They are semi-polished so the builder can finish it their spec.
Please check your local pack rules regarding this type of axles. Some packs do not allow such a modification.