Outside Diameter (in) 7/8. Height (mm) 38. Outside Diameter (mm) 22. Description Headspace Vial, Glass, 20 mm, Crimp Neck, Flat Bottom, 5 mL; 1000/pk. Key Features. Made from Type I Class 51 borosilicate glass. Select from 20 mm crimp neck or 18 mm screw neck vials.