Made from Type I Class 51 borosilicate glass; Select from 20 mm crimp neck or Aijiren Tech 20 mm Headspace Vials, Septum, and Caps For Headspace vials are available in clear or amber glass with a round or flat base, a crimp seal with a beveled or square edge finish, or with a screw-thread G006-10-D/FL – Infochroma AG Crimp vial ND2