Available for all models. Heater specifications: 1.5KW, 120V, 12.5 A. Requires dedicated GFCI circuit. The heater maintains bath water temperature during use and prevents the water temperature from decreasing. Our heater is equipped with automatic reset unlike other heater manufacturers manual reset. Devices that claim to produce heat keeping the bathwater hot by friction have no scientific testing to verify that false claim. Click here for more Info.