This 400K BTU propane gas high performance heater is best-in-class energy efficiency and it heats up fast so no long waits before enjoying your pool or spa. It requires manual gas shut-off while servicing. This MasterTemp is certified for low NOx emission and outperforms industry standards. It has a rotating digital display allows for easy viewing also a tough, rustproof exterior handles the heat and weathers. Measures 36-inch length by 30-inch height by 25-inch width.