Amazon.com: GE, White, Keyless Medium Base Porcelain Lampholder, Mount on 3-1/4” or 4” Box, UL Listed, 18304, 1 Pack : Everything Else
Amazon.com: UltraPro Porcelain Light Socket with Outlet and Pull Chain Light Fixture, Light Bulb Socket, Medium Base, Grounded Plug, Indoor Lighting, Mount on 3-1/4€ or 4€ Box, UL Listed, White, 18305,1-Pack :
E-26 Base Porcelain Lamp Socket with Removeable Mounting Screws.
EPCO 16500 Keyless Porcelain Lamp Holder | Crawford Electric Supply