... orders under customers' demands and different technology desires. 1. Material:NBR,EPDM,SI,FKM(V270M),CR,SBR,IIR,HNBR,ACM,FLS,AFLAS ... -Ring.U-Ring., Oil Seal,PU oil seals , rubber flat washers, rubber Circles, Gaskets, engine parts and accessories,compression mold , etc. 4. Certification ... your requirements ,but o-ring's mold fee is free nbr rubber parts