Vial, crimp top, headspace, clear, graduation marks and write-on spot, flat bottom, certified, 20 mL, 23 x 75 mm, 100/pk. Vial size: 22.75 x 75 mm (20 mm cap) aijiren headspace vials are constructed from type 33 and type 51 COE borosilicate glass, with low metal content, to protect your sample from destablizing or leaching.