Although our industry has not done the best job of describing these systems clearly, the differences are rather simple.

1.	Hydraulic powered pipe rotation,
2.	The ability to safely hang the rotating pipe load,
3.	A sealing arrangement which conducts high pressure drilling fluid from the mud pump through the rotating main shaft or stem.

1.	An elevator and links which may be hydraulically manipulated by the driller to pick up pipe from the mouse hole, the V-door, or the vertical racked position in the derrick,
2.	The time-saving ability to trip pipe without removing the power swivel,
3.	The time-saving ability to drill down with doubles or triples,
4.	The ability to make or break connections above the rig floor by remote control.