**By purchasing this product I understand this product must be installed outdoors by a licensed plumber or qualified pool professional. This product must be factory modified for high altitude locations.** Cupro-Nickel Heat exchangers are standard, making these heaters very compatible with salt systems. Wind condition variables are eliminated, no outdoor stack needed. Improved hydraulics to protect against erosion. Durable Polymer headers and 2" x 2-1/2" CPVC union connections for easy installation and maintenance. Forced draft air moving system. Easy to read L.E.D. control panel with digital temperature read out and diagnostics. Small footprint allows more room at the pad. Limited One-Year Warranty