Closed knuckle design. If you are looking for an axle for a 4x4 swap for a jeep (et al), this isn't highly sought after. Look for later 70's ford trucks. Do you want 8 lug one ton (Dana 44) or 8 lug 3/4 ton (D44)? What is it going into?
Here is the bible:
Pirate4x4.Com - Extreme Four Wheel Drive