That is a valve for a Thetford, but I can't remember what toilet.
What does that sticker say down there? The toilet name, not model number. You will have to cut that clamp and get a hose clamp.
You sure that's where it's coming from?
On the back of the toilet base, the shroud will have two rubber bands right? Take them loose, and take off the shroud; then you can access the valve.
Actually, I think I'll retract all that
It may be a Dometic toilet. Either way, the clamp has to be cut, shroud around base comes off, and then you can get the valve off.