A fuel sending unit measures the fuel in the gas tank by measuring ohm resistance by way of a rheostat connected to a float and lever. This is connected to a gauge located on the tank or in the cabin of the vehicle.When purchasing a fuel sending unit you must match it up to the gauges in the vehicle or aftermarket company specs. The Ohm rating is the resistance rating used to identify what gauge goes with which fuel level sensor. Below is a list of applications for gauge and sender compatibility … read more