Metal pole in doorway that you do situps with......?!

Metal pole in doorway that you do situps with......?

Years ago I knew someone who had one. Its a metal pole that you fix horizontally to the top of an open doorway. Then I think he had some kind of clips that he attached to his trainers. He could then clip himself to the pole, by his trainers, upside down & do situps/ crunches. Does anyone know what these are called & a website where I could get one?
Thankyou.

Hey Bow
I know exactly what you are talking about. A friend of mine has one. Don't know where he got it though. I would imagine any fitness supply/sporting good store should have someting that would do the trick. Good luck!