Standard 2 mL screw-top vial cap kits including. SureStop vials with AVCS cap closures. 2, 4, 8, 16, 20, or 40 mL vial-cap kits. 20 mL glass screw top vials with 24 mm cap closures. Innovative technology ensures proper screw cap seal every time. For use with environmental analyses under EPA regulations.