20mm Crimp Headspace Vial 20mL – MIDSCI Standard 20mm aluminum seal Headspace Vials with Flat Bottoms that form a tight seal with closure for accurate analysis and reproducible results. They are Headspace Vials, ND20, 5 mL, 20×38 mm, Standard Neck, Flat Vials for gas chromatography (headspace vials) are available in different sizes with standard aluminum