... , HRC52 ER nut -Taper 30 degree thread -With Patent products -G6.3 dynamic balance -ISO9001:2008 approval Hardware Products Type A ... and M ER Nut With G6.3 Dynamic BalancingMaterial: SNCM-220 steel, with high aseismicity.Hardness ... molding processing, ensure precision, thread tolerance is 4H.Feature: With G6.3 dynamic balancing, suitable for rpm10,000, and with patent ...