We cemented themselves as the leading manufacturer of mounted ball bearing units on the planet. bearings are 20x26x12 Bearing created with high levels of precision so that they perform under even the most taxing of conditions. bearing is the oldest and largest manufacturer of mounted ball bearing units. They began production of industrial mounted units for the Japanese market, and since then, have become a leading manufacturer of mounted units worldwide.Ball Bearing Units are constructed of high-carbon chromium bearing steel and NSK 6004 Bearing have precision honed raceways and riveted steel cages.