Noritz NRC661-DV-LP Indoor Condensing Direct Tankless Hot Water Heater 6.6 Gpm-Natural Gas/Propane Endless hot water;includes built in display that can preset the output temperature to either 120F, 135F, or 140F Can be vented with Schedule 40 PVC Pipe and Fiiting 93% efficient f or use with natural gas or propane Low Nox design