12x G4 Base Black Lamp Holder Socket Cable, Halogen, LED Bulb Down Light Fitting | eBay
Source GU5.3 G4 GU4 MR16 MR11 Universal Ceramic Lamp Holder Light Socket for LED or Halogen on m.alibaba.com
E-Simpo 10PCS E26 to Gu5.3/GU4/G4/MR16 Adapter- Standard E26/E27 Edison Screw Base to MR16 GU5.3 G4 Gu4 Base Adapter Holder Converter (PBT Material) - Amazon.com
LH0446 G4, G5.3, G6.35 halogen bipin lamp holder/socket with two hole mount and 6" leads
5pcs Mr11 Mr16 Socket Lamp Holder With Bracket Led Halogen G4 G5.3 Gu5.3 Light Socket Porcelain 10cm Long Each - Lamp Bases - AliExpress
4pcs E14 to MR16 Gu5.3 G4 Gu4 Lamp Base Holder Socket Adapter,Euro Standard Candelabra base E14 to MR16 G4 Spotlight Converter - AliExpress
E-Simpo 10pcs E26/E27 to MR16/Gu5.3/G4/Gu4 - Standard E26/E27 Edison Screw Base to MR16 GU5.3 G4 GU4 Base Adapter Holder Converter (Ceramic Material) - Amazon.com
Gu4 / G4 Porcelain LED Bulb Lamp Socket with Clip and Wire - China Lamp Socket, Bulb Socket | Made-in-China.com