4 mm inner diameter (shaft), 16 mm outer diameter (housing), 5 mm width. Dimensions are brand-independent; measure the inner diameter, outer diameter and width with a caliper to verify your part.
Bearings of the same size are interchangeable, but the shield / seal type (open, ZZ, 2RS), internal clearance (C3) and bearing type (ball / roller) must suit the application.
If you are not sure, send us a photo of the part or the code on it; we will find the right product and price.