Low fuel option electrical relay. Stamped C6AF-10A968-A, Ford engineering number C5AZ-10A968-C. This relay was used on 1965-70 Ford and Mercury full sized cars, 1968-70 Torino/Cyclone/Montego/Fairlane, along with 1967-70 Mercury Cougar and Ford Mustang with that low fuel option.
*Note - Generally this will not solve your low fuel indicator problems. The low fuel indicator failure is almost always due to a failed thermistor. The thermistor is located on the fuel sending unit in the fuel tank.