The Pentair MasterTemp 125 heater gives you the energy savings and advanced operating features that were only available from much larger heaters. With its revolutionary pre-mixed gas combustion technology, the MasterTemp 125 heater offers 82% thermal efficiency - the highest of any heater in its category. Its 1-1/2" plumbing is ideal for smaller applications, including above ground pools, spas and in ground pools up to 15,000 gallons. Featuring the first ever rotating, digital display offered in its class, the MasterTemp 125 heater provides valuable information conveniently and at the touch of a button. Plus, its lightweight, compact design makes the MasterTemp 125 heater easier to install than any other heater in its class - reducing labor costs which saves you money.