Premium Pack Clear Glass VOA Vials with Closed-Top Cap. Clear vial designed for volatile organic analysis (VOA) Closed top cap for methods where pierceable septa is not required. Closed top white polypropylene cap bonded with a PTFE-faced silicone liner for a secure seal. Choose from 20mL or 40mL sizes. Directly compatible with automation. Screw Top 24mm Black Plastic Closed Top Vial Cap - Pack of 500