... RINGMaterialNBR,HNBR,SBR,EPDM,FPM,SILICONE,VITON,NR,CR, PU etcSizeCustomized /standard /nonstandardsuch as:GB3452.1-82 ,AS568A ... fieldsAutomotive, Transportation, Filling Machinery, Food Machinery, Oil exploitation, Sanitary plumbing, Medical Machinery, Textile machinery, Mining machinery, Exercise equipment ... Purity Graphite Ring from Baofeng Five-Star Graphite Co., Ltd. High Purity Graphite Ring