... 1) Available material: materials for silicone, NBR, fluorosilicone,viton (FKM), viton DuPont & Dow elastomers, neoprene, HNBR, NBR + PVC, natural rubber, SBR, IR ... , IIR (butylrubber), CR (neoprene), SBR, AU, ACM, CO, etc. NSF-61 approved material, meets drinking water ... specifications are accepted 7) Available in various sizes and colors Foam rubber seal ring