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
10x 12V Halogen LED Lamp Holder Base Socket Plug for G4 MR16 GU5.3 MR11 GU4 New | eBay