Round Lamp Holder: 4" Round Porcelain Lamp Holder with Duplex Receptacle for 4" Octagon Box PF-51-DU - YouTube
GE Porcelain Lampholder with Outlet and Pull Chain, Medium Base, Grounded Plug, Indoor Lighting, 3-Prong, Mount on 3-1/4” or 4” Box, UL Listed, White, 18305, Light Sockets - Amazon Canada
Cion 4 in 1 S.S. Combined with Box with 2,5 pin socket 2,2 pin Socket 4Switch,BULB HOLDER, 6 Amp 240 Volt AC
220v E27 Acoustooptic Control Led Light Socket Holder Adapter Converter On/off For Bulb Lamp Energy Saving Lamp Holder - Pir Motion Sensor - AliExpress
BMW Genuine E46 3-Series Sedan Left Tail Light 4 Bulb Holder Carrier W/Bulbs NEW | eBay
4" Round Lamp Holders for 4" Octagon Boxes and Raised Device Rings - YouTube
Leviton Lamp holder Outlet With Pull Chain | The Home Depot Canada