These precision flanged ball bearings are ABEC-5 rated and conveniently available in singles.

TUH1171
3x6x2.5 Flanged Metal Sealed Ball Bearing
TUH1172
4x8x3 Flanged Metal Sealed Ball Bearing
TUH1173
5x8x2.5 Flanged Metal Sealed Ball Bearing
TUH1174
6x10x3 Flanged Metal Sealed Ball Bearing