8-425 polypropylene screw finished cap with PTFE and silicone septa for chromatography autosampler vial, this screw cap can supply solid and hollow. Screw-top vials also come in different sizes, with vial caps made of either aluminum for crimp seals or plastic. Screw cap are available in 8-425 screw cap, 9mm screw cap, 10-425 cap, 13-425 cap and 24-400 cap.