There are many such bearing structure and size of family, the G2 level of the needle assembly, diameter variation 2um groups within the batch. In addition to full complement needle roller bearings, are using high rigid cage, able to correctly guide the needle parallel to the axis. It is generally a bearing steel of GCr15, customize according to the needs of customer too. Customize according to the needs of customer DETAILS:NK\NKS\RNA49\RNA48\NKI\NKIS\NA49\NA48\RNA69\NA69\RNA49.. RS\RNA49..2RS\NA49..RS\NA49..2RS\RNA0\NA0\RPNA\PNA\RNAV\NAV