70,000, 110,000 & 155,000 BTU input models at 95% AFUE. Stylish, compact wall mount design for easy installation, service and maintenance. Unique condensing stainless steel fire tube heat exchanger design. Built-in boiler circulator. Built-in primary/secondary piping option. Pre-wired terminal strip for quick and easy electrical connections. Convenient indirect-fired water heater connection.