2 7/8 Inch Diameter Lost Wax Cast Eastlake Doorbell (Brushed Nickel Finish) - measures 2 7/8 inches in diameter and top unscrews for easy installation. Solid brass construction - professional Chrome finish for decades of service. Comes complete with the mounting hardware. Uses 24 Volt maximum (standard doorbell circuits). The lost-wax casting process, sometimes known by the French name of cire perdue is an ancient practice that is still used for artwork today and it is used to preserve the fine details of the original Eastlake door bell components.