Thermal Regulator For Mastertemp And Sta- Pool Spa Heaters,and All Sr200 Sr333 Sr400,77707-0010, 38 for heater developed a problem where it turns constantly temperature reached. Simply replace this pool heater thermostat control to rid of the experience where the water temperature take forever to heat up The sta thermistor has undergone extensive testing, means you will a fairly thermal regulator to help your pool spa heater operational, quickly warm the water up and reach the comfortable temperature you . -span matters, 77707-0010 thermal regulator is composed of high-quality metal, which can effectively prevent corrosion and rust, greatly increase the service life even in salt water environment. The thermal regulator kit is designed to use with Master Temp, Sta- Max-E- pool and spa heaters, and it is located between the inlet and outlet water connections on the water manifold. Product kit includes regulator, spring and cap. Colour:Photo Color Material:Composite Materials Package Contents: 1 x Thermal Regulator kit Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm. Note: Due to the light and screen setting difference, the item's color may be slightly different from the pictures. Please allow slight dimension difference due to different manual measurement.