NSK Bearings 6310 zz 2rs nr 1.Deep groove ball bearings 2.High ... steel, iron. 4) Shield / Closure: Plain (Open), Z, ZZ, RS, 2RS, 2ZR, 2Z. 5) Vibration and Noisy level: Z1, Z2, Z3 ... Part of deep groove ball bearing Deep groove ball bearing (ZZ, 2RS ,Z ,RS)604 series605 606 607 608 609623 series623 ... 6304 6305 66306 6307 6308 6309 6310 6311 6312 6313 6314 6315 6316 6317 6318 6319 6320 6321 6322 ...