De GU10 caps are spot bulbs with two pins at the bottom of the bulb. You have to fix it by a quarter turn in the socket. The lights which use GU10 bulbs are directly connected to 220V. A transformer is not required.
First as halogen, today they are plenty of GU10 different bulb in LED version.
SORAA GU10 LED
The best LED bulb GU10 which today exists. Outstanding light exceeding the halogen quality. The colors are perfect and the light is unbelievable, once tested you won't change anymore toward others brand and type light.
PHILIPS EXPERT COLOR GU10
Bulb GU 10 LED PRO of top quality selected by Lamptwist team after a few tests. The light rendition of the LED bulb is close to the halogen.