Heated Ground Bath GUARANTEED to provide your birds with water down to -20 degrees F. Heated Bird Bath dish is 14 in diameter. It nests in a ground level gray granite ring. Ground level Heated Bird Bath is 60 watt thermostatically controlled. Your birdbath is not defective if ice begins to form around the rim. Some icing on the surface of the water is normal when temperatures are this low, especially if there is a breeze. All Erva Heated Bird Baths are made with material certified as flame retardant. Proudly Made In the USA.