Difference between a Mandrel Tubing bender and a?

[mstennes]

Ok I posted a question with a very informative bunch of responses, my next question is a Mandrel Tubing bender the same a tubing bender. I'm not talking about a muffler bender but such as a Tube Shark, JD Squared Model 3, Irvan Smith or a Low Buck Tools hyd? If there is a difference what is it? The reason I ask is I thought a mandrel bender needed something to pull the pipe through the die to get the bends? I dont see anything to do that on these.
Thanks,
Mike