... Feature: 1) Shield / closure: OPEN, Z, ZZ, RZ, 2RZ, RS, 2RS 2) Tolerance codes: ABEC-1, ABEC-3, ABEC-5, ABEC ... d)ISO9001:20001. Seal form: open style, Z, ZZ, RS, 2RS, 2RZ2. Bearing stop ring: N,NR 3. Class of precision ... Feature: 1) Shield / closure: OPEN, Z, ZZ, RZ, 2RZ, RS, 2RS 2) Tolerance codes: ABEC-1, ABEC-3, ABEC-5, ABEC ...