The Vt-75, Visi Therm Heater is a deluxe heater that helps your aquarium maintain a constant, ideal water temperature regardless of room temperature. The unit uses 75 Watts. The Vt-75 includes a direct set temperature dial with certified accuracy of 1 degree and double suction mounting bracket. To use, attach the suction cups onto the heater at the positions indicated and the place the heater vertically or horizontally in the aquarium where there is good water circulation. The unit is fully submersible. Be sure to allow the heater to sit in the water for 15 minutes before plugging in.