... 4,HRB Precision Level :P0 P2 P4 P5 P6HRB is the trade mark of the products of Harbin Bearing Group Co,. Harbin Bearing Group ... as well as more than 50 countries and regions in the world.,widely used in aviation,navigation,gyroscope instruments,precision ... them have been awarede National Silver Medals and the prizes of the Ministry, the province and the city.its machine tool spindle bearings Group ...