... 3.ISO,SGS rubber washer Features:1) Available material: Silicone, NBR, fluorosilicone, viton (FKM), viton DuPont and Dow elastomers, neoprene, HNBR, NBR+PVC ... , natural rubber, SBR, IR, IIR (butyl rubber), CR (neoprene), SBR, AU, ACM, CO, NSF ... specifications are accepted 7) Available in various types for bathroom rubber fittings