Double Linear Ball Bearing EPFC50G 50mm Round Flanged Center MountDouble Linear Ball Bearing 50mm ID Round Flanged, Center Mount featuring a heat treated alloy steel shell for durability. With a low coefficient of friction and a resin retainer polymer cage, this enhanced sized linear ball bearing ensures smooth, quiet, high speed operation and it has an advantage in cantilevered applications over plain bearings. Double seals come standard, enhancing protection at no extra cost. Double size is the equivalent of two