As a manufactory we can supply all kinds of rubber products for you . Features:1) Available material: materials for silicone, ... DuPont & Dow elastomers, neoprene, HNBR, NBR + PVC, natural rubber, SBR, IR, IIR (butyl rubber), CR (neoprene), SBR, AU, ACM, CO, etc. NSF ... in various sizes and colors Inner packing:500pcs/bag silicone valve cores