Product details:

This poultry drinker heater keeps drinkers unfrozen up to -20 degrees F. Adjustable brackets for drinker founts up to 11.5 inches (30cm) in diameter. 100% heat efficiency by perfect insulation. Safe low voltage (24vDC) including adapter and long cable (7.5ft). 100% safe low voltage.Equipped with an adapter, 7.5-foot long cable and brackets.
Brackets adjust up to 11.5-inches in diameter.
Has a power of 28 watts and functions using a 100% safe, low-voltage draw.
Designed to keep water from freezing in temperatures down to -20-degree Fahrenheit.
Developed to provide steady, continual warmth using a non-faulty thermostat.