Reliance condensing propane gas tankless water heater, indoor installations only, 3 major appliance or shower at a time, no standing pilot, 1/2 gallon minimum water flow ignites burner, maximum 199,000 btu input, delivers 8.4 gallons per minute at 45 degree fahrenheit rise, vertical or horizontal venting allowed, vents with 3" or 4" schedule 40 abs, pvc, cpvc, or polypropylene pipe fittings, all venting material purchased separately, built-in freeze protection, 120vac 60hz electrical, digital display, modulating gas valve, 3/4" gas & water connections, propane gas only, water pressure 15 minimum psi to 150 maximum psi, optional kit that includes 2 isolation service valves and 1 required pressure-only valve sold separately, .95 energy factor, energy star qualified, warranty 12 years on heat exchanger, 5 years on parts, meets ultra-low nox emissions ca air quality rules, easy-link up to 4 units, strongly recommend installation by qualified state licensed technician.