Cast aluminum construction for long-term efficiency and performance. Non-stick coating to reduce corrosion and eliminate lime buildup. Thermostatically controlled to operate only when necessary- costs only pennies to operate. Designed for multiple uses around the home and farm. Use in bird baths, buckets of all sizes, small animal waterers, 15 gallon stock tanks and more. Safe for use in plastic. Submersible design with an impressive 5.5 foot long power cord. 3 year warranty.