The Bearing Buddy Bra is specifically designed to keep grease off trailer wheels. Any attempt to overfill axle hubs with grease causes the Bearing Buddy automatic pressure relief feature to operate. If an excessive amount of grease escapes, it can be thrown on the wheels during trailering. The installation of the Bra over the Bearing Buddy eliminates this condition. Models 42101, 42301, 07247, Pair.