Spring in bulb

It looks like a spring but I suppose it is actually called a filament. In the garage I found two tiny light bulbs each 3mm long. When I asked Trev what they were he very helpfully said special light bulbs but had forgotten how they got there or why. It was quite fascinating discovering the coil inside. Some green shiny paper underneath, in the cubby hole with a shallow dof and there we have it.
Some extras to show the other end.