I bought a Thetford 345 for my Little Joe. It short enough to stow under the bed. I got mine on a Amazon Whse. open box deal. I found a similar Porta Potty at Wal Mart for a much better price, it was also a Thetford but a different model number. I made a storage tray out of 1x4s with a 3/8 plywood bottom and flip it over for a 4" riser when in use.