10ml screw top headspace vial is made with a 5.5 mm opening. 10ml screw top headspace vials are designed to work on most autosampler system. The size of 10ml headspace vial is 22.5x46mm, which offers the convenience of screw thread vials for instruments that were originally designed for crimp top headspace vials. 10ml screw top headspace vials are available in both clear and amber glass.