Pentair Heater Master-temp ASME Natural Gas 250,000 BTU P/N: 460771 Master-Temp offer all the efficiency, convenience and reliability features you want in a pool heater, plus a lot more. As easy to use as your home heating system, plus, user-friendly indicator lights make system operation and monitoring a snap. The compact design and super quiet operation won't intrude on your poolside leisure time. Heavy-duty (HD) unit with cupro-nickel exchanger stands up to the harshest of applications, like low pH, high flow or heavy use. Features Heats up fast so no long waits before enjoying your pool or spa Best-in-class energy efficiency* Manual gas shut-off when service is required Eco-friendly Master-Temp is certified for low NOx emission and outperforms industry standards Rotating digital display allows for easy viewing Tough, rustproof exterior handles the heat and weathers the elements