Electrical Fuel Level gauges indicate the fuel remaining in the fuel tank.
This type of VDO fuel level gauge is matched to the VDO Dip-tube type fuel senders (vary between 60 to 90 ohms at empty to ~3 Ohms full), which is required to provide the gauge with the correct input resistance. The gauges have an adjustment potentiometer accessible from the side of the casing to adjust the empty position (to match a particular length of VDO dip-tube fuel sender).
The gauge is supplied with a standard white T10 illumination bulb and 2 coloured bulb covers that can be used to change the night illumination colour from white to green or red. It is supplied with the VDO spin-lok fixing ring.