The Hydro-Quip Pure Heat Universal In-Line Bath Heater is an optimal replacement heater for Whirlpool baths and comes in a versatile, compact size with a convenient 120V 3' corded plug. Its automatic smart thermostat monitors temperature behavior and adjustment levels for an easy-to-use and adaptable heating system, and its in-line configuration supports sturdy pipe connection. The Hydro-Quip Pure Heat Bath Heater's reverse mounting gets rid of direction-oriented installation; both sides can be installed into any standard intake and outtake valve, adapting to 3/4 to 1/2"PVC plumbing.