1985 S-10 with manual brakes. You should also get the set of brake shoes for the S-10. Buy two sets and use the larger shoes in each set. Also get softest shoes possible. Beware when driving on street though, rear can sometimes grab under panic stops.
For these wheel cylinders, the Wagner part# is F110261, the Bendix part# is 33892, and the Industry standard # is W37644. Any parts store can use these numbers to get you the correct wheel cylinders.