Detailed information：
Feature: it is mainly used for grinding the electric spindle round in high speed and high precision bearings, in order to adapt to the requirement of electric spindle, bearing internal parameters for the special optimization design 
B70 series, B72 series, the contact Angle is 15 ° 
Maintains a: outer ring guide phenolic resin maintains a (not a sign) 
Roller materials: steel ball (no sign), ceramics ball (HQ1) 
High precision series are only for the P4 grade, P2 level 
High speed, ultra-high speed, apply to the constant pressure the load, the oil mist or oil-gas lubrication 
Later can choose ceramic ball