An apparatus for the fabrication of a container, comprising a mold defining the form of said container and container and configured to accommodate a substantially tubular preform, an injection head configured to interface with the preform and establish fluid communication with a cavity thereof; an injection valve configured to selectively permit fluid communication through said injection head, and a stretching rod slideably disposed within the injection head; said apparatus further comprising a displacement plunger being disposed coaxially about and mobile relative to said stretching rod between a retracted position substantially within the injection head and an extended position wherein said displacement plunger projects at least partially from said injection head.