This Porti Poti I purchase 20 eons ago.I got it at Sears here in Canada.
Works great. It's a one piece, stores under the front bunks (behind the door).
Comes out at night. I took a plastic milk crate, cut it off 6 inces from the bottom. At night the PP sits on top of it, just the right height ! I can also use this part of milk crate for storing items during travel.