J&K Scientific's Glass Headspace Sample Vials are made of first grade hydrolyzed glass. The bevelled neck and precision screw thread lip allow for a secure seal, ensuring that caps stay on and the integrity of the vial remains intact during volatile sample analysis. These vials are recommended for use with CTC Combi PAL (Varian, Gerstel, Shimadzu, ATAS), HP, Perkin Elmer, and Agilent. These vials come packaged in plastic for cleanliness, as well as a box to ensure that they arrive undamaged.