Scalloped edge allows for easy gripping. 2 inch depth is perfect for birds of all sizes. 17.75 in bowl is ample for several birds at once. Heating starts and stops according to outside temp. Tested to perform in weather down to -20 degrees F. Offer the birds a warm bathing and drinking spot all year round This scalloped Farm Innovators All Seasons Decorative Heated Bird Bath conveniently mounts to any deck railing from 2.75 to 6 inches wide and includes thumb screws. The 17.75 inch diameter bath is big enough for several birds at once and the 2 inch depth is perfect for birds large and small. This bath features a speckled finish that resembles concrete bird baths but the resin material makes it more durable. This bath features a heating element hidden between two layers of sturdy resin and uses a standard 120 Volt AC outlet for power. The element begins to heat the bowl when the temperature nears freezing and turns itself off when the temperature approaches 40 degrees Fahrenheit. A plug on the bottom of the bath connects to any properly grounded outdoor extension cord and a grommet through the deck mount allows the cord to access the plug. About Farm InnovatorsFounded in 1983 Farm Innovators is a leading designer manufacturer and marketer of quality products for farm pet lawn garden pond and wild bird industries. Helping you care for your animals during the cold winter months is their goal and they do this through such innovative products as de-icers for bird baths and ponds and heated pet products like bowls mats and bird baths. Farm Innovators was the first to design and market such items as a submergible tank de-icer heated pet bowl bird bath de-icer and more.