... good quality 4,The materials are bearing steel Specificationsdeep groove ball bearing manufacturer in Shandong. Certification:ISO9001:2008 ... Faster Delivery Steady Quality Deep groove ball bearing1)Material: Gcr15, Bearing Steel, Carbon Steel, Chrome Steel2) ... :6403, 6404,6405,6406,6407,6498,6409,6410,6411,6412. Production Ability: 5,000,000PCS/Month; exporter v groove ball machine bearing 6404