The ETi 400 High Efficiency Heater features the TitanTough™ Direct-Fire Pure Titanium Heat Exchanger, the longest-lasting heat exchanger ever built. And it delivers 96% thermal efficiency, the highest of any pool heater. www.pentairpool.com/ poolfyi.com/ www.facebook.com/pages/Pentair-Aquatic-Systems/295848388965 twitter.com/pentairpool