Eleoption 3KW Water Heater Thermostat Swimming Pool and SPA Heater Electric Heating Pool Temperature Controller (Only Support 220V) (1) Note: Only Support 220V. We will not responsible for reasons order by mistake . So Please check if you need the items before your orders. Thank you. Automatic heating: thermostat will first reach the preset temperature, then stop working until the temperature dropped a few degrees, the thermostat automatically turns on Ultra-high temperature (over 49 C), ultra-high temperature switch will automatically trip (power off) T thermostat operation is fully automated, clockwise, the heating is on, indicator light, temperature reaches a preset temperature, will remain at that temperature The thermostat can be maintained within a temperature not exceeding 40 C (104 F) range. If cold water is started, will be 6 ~ 8 C / h elevated temperatures