The Fluidmaster Bowl Gasket slips into the waste flange using an O-ring rather than wax to create a waterproof seal.
We installed this Kinetico 2020c in cramped quarters where a traditional unit would never fit.
The Takagi T-KD20 that we installed is about the size of a carry-on suitcase and mounts directly on a wall. It is capable of matching the production of the 40-gallon tank-style heater that it replaced.