... silicone O ring 1.any size for silicon O ring 2.Non-toxic,Waterproof,Dustproof 3Under high wear and pressure 4.OME welcom silicon O ring ... Features:1) AS-568, PG standard and non-standard Silicone O-rings 2) Various colors ... ) Available materials: silicone, fluoro silicone, viton(FKM), neoprene, HNBR, NBR+PVC, NBR, natural rubber, SBR, IR, IIR(butyl rubber), CR (neoprene), ...