The patented 11 mm Poly Crimp™ Seal is versatile: it permits an airtight seal by hand or use a standard crimping tool. Polypropylene construction means no more sharp edges. Polypropylene Crimp Top Caps for Chromatography Vials crimps and decaps smoothly and easily and holds the septa firmly in place. The Poly Crimp™ Seal aligns itself on the vial neck to eliminate inconsistent sealing and fits virtually any crimp top sample vial. Available in a variety of colors for easy sample identification.