Pressure release aluminum crimp caps for all 20 mm Headspace GC autosampler vials, including Aijiren, Hewlett Packard, CTC, PerkinElmer, Tekmar, and LEAP vials. PTFE-faced gray butyl rubber septa. Best resealing for multiple injections. For use with water matrix samples. Recommended for use from -40 to 120° C. Preassembled. 1,000 Caps Per Case