3-Way Mogul Lamp Sockets generate 100, 200 and 300 watts of light producing three levels of luminosity. The large size, 4-1/4" height including base x 2-3/16" diameter, is considerably bigger than standard sockets. Use as a center replacement socket on three arm reflector floor lamps and other large lighting devices. Large metal base has a ½" opening to screw onto ¼ IP pipe. Turn knob switch. Use this is excellent quality socket when restoring antique and vintage lighting.