The Rheem Millivolt Plus Natural Gas Polymer Heater is a powerful gas-fired pool and spa heater with a high flow rate and fuel efficient design. Featuring an all copper fin tube heat exchanger, stainless steel tube sheet, and a PolyTuf textured powder coating, Rheem heaters are durable and reliable any environment. Rheem Heaters come with a set of 2" slip-fit CPVC water connections, which make for a secure fit and an easy installation process. Trust Rheem pool and spa heaters to deliver unprecedented heating performance for your pool or spa.