Halogen bulbs can be dimmed, which is perfect if you want to adjust the lighting level at home. The socket on this bulb is a so-called G4 socket.
From Amazon
Osram Starlite Halogen Light Bulb G4 12 V 4000 h 20 W
Lamps 2U Direct
Osram 64425 20 watt G4 Halogen Axial Filament Capsule Light Bulb