With two structures of bore cylindrical or tapered and retainers made of steel sheet or syntheticresins, the bearings are characteristic of compensate concentricity and deflection errors.The bearings are available in open and sealed versions.Self-aligning ball bearings are for heavy load and shock load , precision instruments, low noise motors, automobiles, motorcycles, metallurgy, mill, mining, petroleum, paper, cement, sugar, and other common machinery.