Matt he means two piece axle where the flange that the wheel bolts to is separate from the axleshaft. The flange is attached to the axle via a keyway and a nut on the end of the shaft. No hubs, no full floater.

These axles do not have the notoreity for spinning the flange like AMC 20's do. To what extent they are stronger I don't honestly know. I believe Superior makes a one-piece, forged axleshaft to replace these.