... high-quality products at rational prices and best service . Features:1) Available material: materials for silicone, NBR, fluorosilicone, viton (FKM), viton ... elastomers, neoprene, HNBR, NBR + PVC, natural rubber, SBR, IR, IIR (butyl rubber), CR (neoprene), SBR, AU, ACM, CO, etc. NSF-61 ... in various sizes and colors Inner packing:500pcs/bag Silicone_Valve_Cores 1