Detailed Product Description deep groove ball bearing is widly used all over the word, agriculture, industry,construction,electric equipment,and so on. And the material include chrome steel and carbon steel. zz ,rs,2rs ,ddu,are different seals on the groove,zz and ddu are iron seals,rs ,and 2rs are plastic seals.All of the bearings have passed ISO9001:200 and AAA systerm.We accept small orders.