This 'thing' is used by solid halogen-tracks (12V) in order to keep the tracks separated and to keep the halogen lights in a distance from the ceiling it is attached on. After having broken one that came with the system, the dealer was not willing to hand me over a spare-one. He rather wanted me to buy a completely new system...

Hey, it's a 'thing' made of plastic! Fine... so I printed it myself.

This thing was made with Tinkercad. Edit it online https://tinkercad.com/things/6C9sxhDK6re