... materials: EPDM NBR VITON HNBR PU PTFE PA SI Viton O ringSuitable for hydraulic pneumatic parts,and machinery equipment inrotary or ... .2)Pressure:No Halted Ring less than 40kg/sq.cm(according to o-ring material).3)Material:PTFE,NBR,SI,VITON,HNBR ... .76mm to 677 mm3) Standard of China(o-ring GB3452.1-82),Standard of American(o-ring AS568) and Standard of Japan ...