marine pneumatic butterfly valve wafer eccentricity a) materials:steel b) operation mode:manually operation,pneumatic Marine pneumatic butterfly valve wafer eccentricityValves standard : GB,JB,JIS,API,CBM etc.Material : cast steel,cast iron,cast copper,forged steel,stainless steel,plastics,etc.Certification : CCS,LR,BV,ABS,DNV,GL,KR. marine pneumatic butterfly valve wafer eccentricity