Membrane Solutions Headspace vials are available in clear or amber glass with a round or flat base, a crimp seal with a beveled or square edge finish, or with a screw-thread finish. The vial in flat Bottoms is generally common with Agilent, DANI, Fisons, Perkin Elmer and Shimadzu GC instrument, and Rounded Bottoms for Perkin Elmer, Tekmar, CTC PAL, and Varian.