Fully modulating, gas fired, tankless water heater with sealed combustion and power vented flue. Supplies hot water to domestic hot water systems (directly or indirectly) and can be used with water storage tanks, recirculation systems, and/ or combined domestic & heating applications. 15-year limited Heat Exchanger Warranty, 5-year parts warranty, 1-year labor warranty for Residential applications 5-year limited Heat Exchanger Warranty, 5-year parts warranty, 1-year labor warranty for Commercial applications Commercial Grade Copper Heat Exchanger Ultra-Low NOx emissions Convertible from Natural Gas to Liquid Propane Easy-Link up to four units without a Multi-Unit Controller Multi-Link up to 20 units with a Multi-Unit Controller Non-Condensing Concentric Vent Indoor model Supplied with a power cord