actually theres a knockoff on the net for 169 bucks without the bullshit weight system tracman gives. its the sames as a pump tube but it has a hook built into the tube and a very thin ,stiff piece of rubber at the opening that acts as a seal. if you have pumpt tube , pump up and pull on the tube and youll feel your ligs stretch. to answer your question the skin does get pulled foward somewhat! if you call stretch willy the guy that runs the place answered all my questions and is cool to talk to, so maybe he could exsplain better than i can how all this is working ,but if you read the post on the peforum you mite be able to make one yourself.