I bought these to replace the top bearings in the mower blade mounts. The bearings appear to be of good quality but are very poorly lubricated. They arrived in a small plastic sleeve containing all 10 bearings. I went ahead and bought them after reading reviews of lube so I carefully removed the seals to find almost no lube and what was there turned out to be petroleum jelly. I cleaned everything that was there and filled the bearings with fully synthetic molybdenum wheel bearing and constant velocity joint grease and then reinstalled the seals. Now they should last a very long time. The time will show.