EPA vials with PP cap, KIMBLE®. Supplier: DWK Life Sciences. These EPA water analysis vials with screw thread closures are ideal for the collection and storage of water samples. Open-top. Made of borosilicate glass. Vials are not pre-cleaned. White PP closures with PTFE-faced silicone rubber septa. Certifications: Glass conform to USP Type I and ASTM E438, Type I, Class A requirements.