The ATHR-160X3 Adapt®+ Premium condensing gas tankless water heater uses up to 160,000 BTUs of Natural Gas or Liquid Propane to deliver a max flow rate of 10.5 gal/min. A. O. Smith’s Adapt® premium condensing gas tankless water heaters deliver robust, on-demand performance and the flexibility to install in virtually any residential setting.Built-in X3® Scale Prevention Technology helps maintain like-new performance by protecting the heat exchanger from build-up. Scale-prevention protection can prolong the life of the heat exchanger by up to 300% compared to an unprotected unit.The Adapt® line features a built-in Control Display for setting and reviewing up to two recirculating schedules—as well as checking heater status and error codes. Manage temperature settings and activate the heater and recirculation pump remotely with optional kits (sold separately).All models are ENERGY STAR® certified with a Uniform Energy Factor of 0.95 and comply with Ultra-Low NOx regulations. All Adapt® models are field convertible from Natural Gas to Liquid Propane (kit included) and can be installed indoors or outdoors with an Outdoor Vent Cap Kit (sold separately).Cascade up to 12 like heaters together for larger applications requiring multiple water heaters to work in conjunction, cable included.