Aijiren’s 2ml clear screw hplc vials for autosampler is usually divided into three types of calibers. 2 mL Standard Opening Vials from Aijiren. Our standard 2 mL vial is 12 mm in diameter, 32 mm in height, and has a 4.6 mm opening. The main application for HPLC, autosampler, chromatography, Aijiren, waters machine.