Headspace vials are made from 51-expansion type 1 borosilicate glass. The lip has a beveled shape (slightly raised inner edge) for tight seals. The dimensions for our Headspace Vials are: 6 ml, 22 x 38 mm; 10 ml, 22 x 46 mm; 20 ml, 22 x 75 mm; 27 mm, 30 x 60 mm.