... prices and best service. Features:1) AS-568, PG standard and non-standard size O-rings 2) Various colors available, such as black ... ) Available materials: silicone, fluoro silicone, viton(FKM), neoprene, HNBR, NBR+PVC, NBR, natural rubber, SBR, IR, IIR(butyl rubber), CR (neoprene ... physical property6) Customers' designs and specifications are acceptedPacking:500pcs/bag Standard O_Rings