The 9mm Short Thread Caps that are included with this kit are knurled on the sides for excellent gripping and comfort when applying to the vial. Caps for screw thread vials are available with either an open hole for autosampler use and standard addition or with a solid top for sample storage.Screw Cap Vials are universal. Screwing the cap applies a mechanical force that squeezes the septum between the glass rim and the cap.
