The Electric Water Fountain Heater works with 1, 3 and 4 gallon poultry water fountains. Includes a built-in thermostat with auto shut-off. This electric heater base is ideal during the winter months in order to keep your metal poultry drinkers from freezing. This unit only keeps the water warm enough to prevent freezing. This heater base can also be used with watering pans and other various types of game bird waterers as well.