Silicone O-ring Materials: different kinds of rubber & plastic, such as Silicon, NBR, SBR, NR, CR, EPDM, and FKM Silicone O-ring Features:1) ... Materials: different kinds of rubber & plastic, such as SILICON,NBR,SBR,NR, ... the ISO-90015) RoHS directive compliant green products6) Customer's design and specifications are accepted7) Available in various sizes ...