... (FKM), viton DuPont & Dow elastomers, neoprene, HNBR, NBR + PVC, natural rubber, SBR, IR, IIR (butylrubber), CR (neoprene), SBR, AU, ACM, CO ... support and samples 6) Customer's design and specifications are accepted 7) Available in various sizes and colors Rubber silicone valve core