2mL Standard Opening Vials. Our standard 2 mL vial is 12 mm in diameter, 32 mm in height, 5.5 mm opening. The thread size on this vial is 8-425. Choice of clear or amber glass. These vials are the very best available today for HPLC, GC, LCMS & GCMS. Aijiren screw thread top 8-425 sample vials design is characterized by the use of automated