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 ,23050-340CS,89202-876CS,23050-298CS,23050-030CS,23050-078CS,23050-026CS,89202-884CS.