Our associated crimp caps and closures come with a choice of etiher PTFE silicone, PTFE only, natural red rubber, butyl, or PTFE butyl materials. Our 11 mm crimp top vials and crimp caps are the perfect fit for HPLC and GC instrument platforms across a wide variety of applications, including pharmaceutical, environmental, energy and fuels, forensics, materials science, biopharmaceutical