I am using this bearing in an wet corrosive enviromnmt at relatively low RPMs and low load. The application requires very low drag where sealed metal bearings cannot be used and grease or oil would contaiminte the solution. Without the seals the bearings freeze and require frequent replacement. Glass ball bearings with acetal inner outer races are not chemically campatible. The full ceramic bearings are great! The bearings are fairly expensive but I expect to last a very long time and well worth the initial cost.