The Farm Innovators Heated Rock Birdbath De-icer is a cast aluminum artificial rock that has an economical low-watt heater built-in to maintain open water in your birdbath even in sub-zero temperatures. The Heated Rock Birdbath De-icer features 75 Watts of power that is thermostatically controlled to operate only when temperatures fall below 35 degrees Fahrenheit to save and conserve expensive energy. Its durable cast aluminum shell has a natural color that fits in with virtually all birdbaths but it may be painted to match any birdbath. This de-icer is safe to use in all birdbaths. Dimensions: 5.25L x 5.25 W x 1 H.