... reliability and durability of bearing seal.Main Type Available Size: 6",6 1/2",7 1/2",8 1/2",9 1/2",9 5 ... Series, 5-- Series, 6-- Series,etc. 2. Elastomer sealed bearing TCI BitCutting Structure The durability of premium tungsten carbide insert is improved ... Bearing Structure 1.Abrasion resistance and seizure resistance of the bearing are improved. 2.Premium O-ring, Optimal seal compression and curved ...