Product details:

Allied Precision's 250 Watt Bird Bath De-Icer has a low profile, sturdy aluminum base incorporating multiple thermostats for efficient, accurate temperature control and a 10 foot cord making this unit ideal for keeping your bird bath ice-free all winter long. This bird bath de-icer is energy efficient, as it does not overheat the water. The large heating surface area runs cooler than conventional de-icers. It has a low profile for easy placement in your bird bath. This de-icer operates over a narrow heating range.Thermostatically controlled de-icer, can be used completely or partially submerged in bird bath
Set to turn on when water goes below 32 degrees
Includes an adjustable clamp so you can attach the de-icer directly to the water container
Safe to be used in plastic bird baths