4 oz (120 ml) Natural polypropylene high profile custody hinged vial with sodium thiosulfate tablet & break off arrow lock seal tab & custody string. Polypropylene hinged vials are leak-proof and airtight and are produced by using a sterile-by-process (aseptic) method. hinged vials are manufactured using a unique, patented process that closes the vial lid while still in the mold and prior to ejecting the container. The process uses temperatures ranging from 390-440 degf which is too high to support living organisms. hinged vials remain closed until they are opened for the first time by the user. The flip-top is integrally hinged to the container, allowing the user to open and close the container with one hand.