About the middle of December there was a post on here from a guy that worked for Dometic offering porta potties at a special price to FBRV owners. I made the mistake of buying three, two as gifts. They are totally undersized and not made for adult bodies. Their webpage only gives outside measurements, not what size the seat would be. I am in dispute with Dometic and have notified my credit card company.
Just saying BUYER BEWARE. I will post info on my resolution from Dometic as I expect them to stand behind their products and brand name.