|48204 - Leviton Brand Short Keyless Medium Base Socket Interior|
|40204G - Leviton Brand, Keyless Socket|
|40266 - Leviton Brand Keyless Plastic Medium Base Bakelite Socket|
The more complicated keyless socket is a 3-way socket. Designed for 3-way bulbs, the 3-way socket has the extra contact point on the base of the socket. 3-way bulbs have a low, medium, and high setting from having 2 sets of filaments.
|On-Off PushThru Socket Interior|
|On/Off Turn Knob Socket Interior|
|3-Way Turn Knob Socket Interior|
|48220i - 3-Way Keyless Socket Interoir|
|40402N - 3-Way 2 Circuit Nickel Rotary Switch|
The switch has 4 positions and the socket has 3 screw terminals. As the diagram shows, the smooth lamp cord wire connects to the black wire of the switch. The ribbed lamp cord connects to the nickel screw terminal on the socket. The red wire is the first circuit to turn on so it connects to the brass plated screw terminal and the blue wire connects to the black screw terminal. In the 4th position of the switch, both red and blue wires are on the closed circuit and the 3-way bulb has both filaments lit.