Misakomo Thermal Regulator Compatible with MasterTemp 400 250 125 200 300 333 Models and Sta-Rite Pool Spa Heaters SR200 SR333 SR400 Models, Replace# 77707-0010, 38000-0007SBrand: Misakomo Features: NEEDSAs time goes on, your heater developed a problem where it turns on and off constantly before target temperature was reached. Simply replace this pool heater thermostat control to get rid of the experience where the water temperature take forever to heat up. FASTER HEATINGThe mastertemp sta rite thermistor has undergone extensive testing, means you will get a fairly reliable thermal regulator to help get your pool spa