... ,C3,C4 4.widely usedsingle row cylindrical roller bearings, caged ,mainly of the NU,NJ NUP ... and N designs double row cylindrical roller bearings ,caged,mainly of the NNU and NN ... designs double row full complement cylindrical roller bearing bearings,mainly of the NNF design multi-row full ... complement cylindrical roller bearings, with four or eight rows of rollers Welcome ...