GPI Thread Finish: 13-425Shell Material: PolypropyleneLiner Material: F217 PE FoamCap Color: Black Magnakoys 13-425 Continuous Thread Black Screw Closure Caps. Cap your 1/4, 1/3, 5/8 and 1 Dram vials with the perfect closure. Available with different liner materials to insure compatability with virtually any material. It is essential to determine the appropriate closure for your application. See our images to determine what size cap you need for your vials or bottles. Thank you for looking !!!!