... -ring,x-ring. Material are :FFKM,NBR, HNBR,EPDM,SI,FKM(VITON)CR,PU,PTFE,ACR(A) 1. material:NBR,EPDM ... ,SI,FKM(V270M),CR,SBR,IIR,HNBR,ACM,FLS,AFLAS ,PU ,etc2 ... . Y-Ring.U-Ring., Oil Seal,PU oil seals , rubber flat washers, rubber Circles, Gaskets, engine parts and accessories,compression mold , etc ... ,but o-ring's mold fee is free. KTW standard rubber seal