The 55 mm steel shaft sleeve bearing compatible with bearing numbers 6011, 6211, and 6311 features a sleeve length of 50 mm, designed to fit precisely with these deep groove ball bearings. The 6211 bearing, for example, has an inside diameter of 55 mm, outside diameter of 100 mm, and width of 21 mm, with a C3 internal clearance for thermal expansion and high-speed operation up to 9,500 RPM (oil-lubricated). These bearings are shielded or sealed to protect against contaminants, pre-lubricated for durability, and suitable for electric motors, industrial machinery, and automotive applications, offering reliable performance and extended service life.