1968-1982 Headlight and Wiper Door Relays - Pair.  These commonly wear out and will leak air causing a lot of headlight problems.  Please reference online diagnostic troubleshooting for easy way to test if yours are bad.

1968 Requires 1 for the wiper door & 1 for the headlights.

1968 - 1972 Requires 1 for the wiper door & 2 for the headlights.

1973 - 1982 Requires 2 for the headlights.