The product was a huge disappointment. As my tests showed, the bearings were poorly manufactured and did not perform well under even moderate loads. The lack of consistency in construction and finish makes them an unreliable choice for industrial and scientific applications. The only redeeming factor is the relatively low cost, but even that does not justify the risk of costly downtime and maintenance issues. Overall, I would not recommend these bearings to anyone looking for quality and durability in power transmission products.