... the inner ring, outer ring, cage assemblies and steel balls. 2. Bearing materialChrome steel, Carbon steel, Stainless steel...etc; 3. Bearing ... type:1): Open, metal sealed(ZZ) or Plastic seaed (RS)2): Single-row, double-rows3): Normal ring series, Thin-wall(ring ... groove ball bearing 6000,6200,6300,6400,6700,6800,6900,4200 series