9 mm Wide Mouth Vials and Closures are our recommended screw thread vials. These vials are autosampler compatible and offer a 40% larger opening than 8-425 thread vials, simplifying pipetting and other routine functions. Amber glass vials are perfect for storing samples that are sensitive to light exposure. Clear glass vials are great for testing the solubility or dispersability of materials, allowing you an unhindered view of the solution.