These heaters are designed for use in outdoor ponds with fish in the winter season, when the surrounding temperature falls below 0 deg C. These high quality floating pond heaters keep an area of the pond surface around the heater float ice-free to allow oxygen exchange to take place, and to allow any poisonous gases to escape.
The unit comes with :
Stainless Steel Heater : 360mm long (not adjustable) with 10 metres of mains cable
Stainless Steel Heater Guard : 320mm x 50mm diameter
Plastic Domed Cover : 240mm diameter
Note : Heater must not be operated out of water. In the event of the unit overheating, an internal thermostatic switch will turn it off, and reset when temperature reduces
(The manufacturer gives no indication of minimum operating conditions, nor which heater wattage is most suitable for a specific application. Obviously the 300 watt unit will be more effective at lower temperatures than the 150 watt unit.)