Comparison : Item # 21304, 21300 Series Spherical Roller Bearings
Item # 21305, 21300 Series Spherical Roller Bearings
Item # 21306, 21300 Series Spherical Roller Bearings
Item # 21307, 21300 Series Spherical Roller Bearings
Item # 21308, 21300 Series Spherical Roller Bearings