Precleaned VOA Vials, Environmental Express®. Supplier: Environmental Express. Description: These volatile organic analysis (VOA) vials are made of borosilicate glass. Choose from an open-top cap (0.125" thick PTFE/silicone septa) or closed-t ,23050-386CS,89202-874CS,89202-876CS,89202-866CS,23050-384CS,89202-870CS,23050-010CS.