Source Light bulb socket adapter GU10/PET extender Mr16 to GU10/E27 to GU10 plastic converter on m.alibaba.com
Amazon.com : E-Simpo® 12pcs MR16 to Gu10 Light Socket Adapter, LED Halogen MR16 to GU10 GU5.3 to Gu10 Spotlight Lamp Base Holder Converter, Need Remove MR16 Transformer if Old MR16 is 12V
MR16 GX5.3 GU5.3 male to GU10 female Converter Adapter - Converters - LEDLight