The Sapphire Series 12L Natural Gas Type is an 80,000 BTU indoor tankless water heater capable of producing up to 4.4 GPM. with low water flow ignition, the SAP12 will ignite at just 0.5 GPM It's designed to save you space and lower your overall energy costs up to 40% versus a traditional tank type water heater. with utilizing an electronic ignition that only ignites when you open a hot water tap, no longer will you waste money on a standing pilot light. Digital controls allow you to adjust the temperature with a simple push of a button. Save money on Energy bills and enjoy the benefits of endless hot water by switching to a tankless water heater today.