Does not come with caps. 13mm Screw Thread Autosampler Vials are made of USP Type I, N-51A borosilicate glass, amber 2.Sample Vials with unique thread design ensures consistent seal and can be reused, not volatile, easy to use 3. 4ml Amber autosampler vial,15mm Diameter, 45mm Height, 13-425 screw top 4.