... form: open style, Z, ZZ, RS, 2RS, 2RZ2. Bearing stop ring: N,NR3. Class of precision: ABEC-1, ABEC-3, ABEC ... , PTFE, nylon9. Bearing ferrule and ball hardness: 59 - 63HRCSeals:Seals, seals, oil seals, seal, shaft seal, hole seals, dust seal, guide ring, fixed ...