They are compatible with most HPLC and GC autosamplers. Phenomenex Vial Part: Verex™ Crimp Top Seal, 20mm Dia., PTFE . Vial Part: AR0-5255-12 Verex™ Crimp Top Seal, 20mm Dia., PTFE/Silicone, magnetic cap, gold, 100/Pk . Crimp top vials and caps | Lab Unlimited UK. Crimp caps can be used for crimp top vials and for vials with snap ring design.