flat bottom 20ml headspace vials in amber manufacturer Vial, crimp top, headspace, clear, certified, flat bottom, 10 mL, 23 x 46 mm, 100/pk. Vial size: 22.75 x 46 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 Certified 20ml screw gc.