This burner tray is designed for the Gas-Fired Pool and Spa Heater Bronze ASME and Polymer Atmospheric Heat Exchanger Models 399, and 406A. The sleek and stylish Raypak ASME Digital Gas Pool and Spa Heater features innovative technology designed to keep your pool or spa at the perfect temperature for your enjoyment. Built to withstand various weather conditions, this modern pool and spa heater is the perfect solution for environments requiring efficiency, convenience and versatility.