This 400 BTU propane gas ASME certified MasterTemp pool heater, heats up fast so no long waits before enjoying your pool or spa. Best-in-class energy efficiency and requires manual gas shut-off while servicing. MasterTemp is certified for low NOx emission and outperforms industry standard. Tough, rustproof exterior handles the heat and weathers the elements. Measures 36-inch length by 30-inch height by 25-inch width.