9mm Plastic Screw Thread Vials are manufactured from GC-tested polypropylene. Marking Spot, Graduated. Volume (Metric) Usable, 1.5 mL. With Our Simplified Selection of Chromatography Vials - Restek. Precision Sampling GC111, GC 311, LC 241-60 Short-Cap Vial without Graduated Marking Spot 1.5 mL Versa Vials™, Polypropylene, 12 x 32 mm.