220V, 3KW, 1.5" outlet, minimum working pressure of 0.35MPA. A minimum of 0.25HP/200W (1500GPH) pump is recommended to ensure the hot tub heater will work properly. Products are suitable for small 340 gallon tubs and spas/hot tubs up to 600 gallons. The water heater thermostat stabilizes the water temperature between 0-45ºC (32ºF~113ºF). The thermostat will automatically turn on or off depending on the temperature you set. If the temperature exceeds 60ºC/139ºF, the heater will stop working and the reset button will pop up and cut off the power. Please put hot water instead of cold water into the hot tub, the heating time will vary depending on the environment and water temperature. Since the tub heater is equipped with a flow switch, the tub heater will only operate when the pump is running. Easy to install, you will get 1*220V/3KW hot tub heater and 2PCS pipe connector (pipe is not included, you need to prepare 1.5 inch hose extra), please install the hot tub heater horizontally and make sure the installation direction is correct, the water flow direction should be the same as the arrow direction on the heater.