Comparison : Item # ER1038ZZS, 0.3750 Inch (in) Bore Diameter (d) Extra Thin Shield Metric ER Series Ball Bearing
Item # ER1212ZZS, 0.5000 Inch (in) Bore Diameter (d) Extra Thin Shield Metric ER Series Ball Bearing
Item # ER1458ZZS, 0.6250 Inch (in) Bore Diameter (d) Extra Thin Shield Metric ER Series Ball Bearing
Item # ER1634ZZS, 0.7500 Inch (in) Bore Diameter (d) Extra Thin Shield Metric ER Series Ball Bearing