... 2. Materials: GCr15, GCr15SiMn, G20Cr2Ni4A etc Ring and cages: Chrome bearing steel Balls: Chrome steel or carbon structural steel Cover: Rubber ... : P0, P6, P6x, P5, SP, P4, UP (ABEC1, ABEC3, ABEC5); 5. Noise Level: Z1, Z2, Z3; 6. Vibration Level: V1, V2 ... /9001/9004/19011: 2000 ISO 14000/14001, OEM available Needle Roller Bearing