The transformer of the old halogen bulbs of the mirror burned out, and it was time to switch to the more energy-saving LED lamps. My choice is the spotlights with GU10 socket, but that the supports on the market are all too wide to fit my mirror.
So I designed this adapter: the external diameter is 52 mm, the internal is 50 mm (the standard for this type of spotlights). It remains fixed by interference, but I still designed the attachment for the support spring.