Miniature bearing selection starts with three envelope dimensions: bore diameter, outside diameter and width. A small dimensional difference can change fit, preload and available speed.
When replacing an existing bearing, record the complete model marking and verify the measured dimensions. For new designs, share a drawing that identifies shaft fit, housing fit, speed, load direction and operating temperature.
Seal type, precision grade, internal clearance, noise requirement and lubrication should be selected around the application rather than treated as independent line items.