Screw Top Vials: Standard (4.6 mm) and large opening (6.0 mm) vials are available in both clear and amber glass. They come with a variety of closures and septa. 9 mm Screw Top Vials: These large opening (6.0 mm) vials have a unique thread design that allows you to screw on the caps, and still use them in a robotic autosampler. This thread is