Caps for VWR® 9 mm Screw-Thread Vials. Supplier: VWR International. Description: VWR Autosampler Vial Screw Thread Cap, Color: Yellow, Material: Polypropylene, Septum: Red PTFE/White Silicone, Thickness: 1.0mm, 6mm hole, applications: Industrial Chromatography, optimal and also consistent seal, Size: 9mm. Certificates.