Our 2mL 12 x 32mm standard mouth vials have a useable volume of 1.5 ml and are available in 8/425 and 9/425 screw-thread polypropylene cap style or 11 mm aluminum crimp cap style. Septa liners are made from silicone or butyl rubber to create an effective seal, and are faced with a chemical resistant, ultra-pure barrier of PTFE.