Temperature Controller Thermostat 1000W Heater Heating AC100~240V Aquarium tank Globally 1000W AC100~240V 50/60 Hz For aquarium in-door use only. Check power supply, power outlet, and voltage in comply with rated values. To set desired temperature, turn the adjustment knob of Thermostat to the desired temperature. Put Heater into aquarium, submerged in full, at a position with good water circulation.