Leviton 3152-8 Medium Base, One-Piece, Keyless, Incandescent, Unglazed Porcelain Lampholder , White - Light Sockets - Amazon.com
Leviton Mogul to Medium Base 660W White Porcelain Socket Reducer - Baller Hardware
Leviton Turn-Knob Medium Base Brass Lamp Socket - Gillman Home Center
Leviton 30 Incandescent Lampholder, Medium Base, Two Piece Porcelain; 660W-600V; Keyless; with Two 8-32 By 1/2 Inch Long Mounting Screws. - Light Sockets - Amazon.com