Designed to work with most American Standard whirlpool tubs, this Safe-T Heater helps maintain a consistent water temperature for a longer, relaxing soak. The unit is equipped with a pre-set pressure switch (pump must be running with the water flowing during heater operation). Includes an intelligent high-limit that prevents hot tap water from falsely tripping the safety circuit and turns off the heater if the thermostat fails. Requires a separate 120-volt AC/15 Amp dedicated circuit with GFCI protection. - OPEN BOX