The PGN shielded bearings I purchased for my industrial machinery have exceeded my expectations. After I put it to the test I noticed a significant improvement in the smoothness of operation .The lubrication has lasted longer than other bearings I've used in the past, making them a cost-effective choice. As an added bonus, they are easy to install. The only downside is that they are slightly more expensive than other bearings, but the quality justifies the cost. Highly recommended for any industrial and scientific APPLICATION!