Leviton White Porcelain Incandescent Keyless Lampholder

1-piece, glazed porcelain lampholder. Features 4 screw terminals for continuous wiring and knockouts to fit a 3-1/4 inch or 4 inch outlet box. Twist-lock mounting provides quick and easy installation. 660-watt/250-volt. UL (Underwriter's Laboratories) and CSA (Canadian Standards Association) listed. 4-1/2 inch outside diameter.