My 2013 Unity has a Dometic 300 toilet. I recently found out it's on recall because of a problem with the inner seal ( experienced the overflow problem!). Since it is not the original toilet, I don't know what to replace it with. I can get Dometic (replace with an upgraded 300, or with 310 or 320). I've found some evidence there was once a 310. That unit was not plastic. Currently the 310 is plastic. I also found information about a Thetford, but with no selection of a particular model. I am the third owner of this van, and a full-timer who needs to correct this unreliable toilet! Thanks for your help and feedback.