... structure.Features : Shield / closure: open ball bearing, Z, ZZ, RS, 2RS,2RZBall bearings snap ring: N, NRTolerance codes: ABEC-1, ABEC ... : Ball bearings with one or two side rubber seal RS, 2RS.With one or two side metal shields Z and ZZ ... 6300 6400 series , u groove ball bearing , bearing skf 6406-2rs 6406 2rs 6406 rs