These caps were not offered by Ford but should have been. Even with hobby use the wheel bearing grease can become quickly contaminated by dirt and moisture. These caps are simply an upgrade to offer protection like more modern vehicles have. Most Model As require 1/64" to be removed off of the outside diameter of the bearing washer to use these caps. This can easily be accomplished with a file or grinder. Purchase two per vehicle and kiss repeated wheel-bearing packing good bye!