Aluminum Crimp Seals ND8. 1.2.1 Natural Rubber/TEF and RedRubber/PTFE Seals. Headspace Vial ND20 clear glass for CTC PAL (Varian, Gerstel) Via. Headspace-Vial, ND20, 20 ml volume,75,5 x 22,5 mm, clear glass,DIN crimp neck, The various cap-types which are suitable for the vials are colour-coded. With Our Simplified Selection of Chromatography