Raypak 014784 - 156A Natural Gas Pool Heater is 150,000 BTU and uses 120V or 240V for installation. This unit is rated for 0-4999ft Elevation and uses corrosion Polymer Headers. The Raypak 156A is the perfect choice for above-ground pools and spas. Raypak is the only manufacturer of this size heater to use all the engineering and components utilized in our bigger gas heaters. The unit is fully serviceable and built for years of operation. This may be our smaller sized pool and spa heater, but it's built to the same exacting standards as the rest of our products. Extend your swim season, open your pool earlier and close it later. Your pool is always ready when you have a Raypak on duty.