11mm Patented Snap Top Caps™ may be snapped on and off by hand which eliminates the need for metal crimping and decapping tools, thus reducing potential hazards due to sharp aluminum metal edges. Large opening top provides a greater target area for needle penetration. Linerless Snap Seal™ Caps for Chromatography Vials are available with or without starburst. Starburst allows for easy needle penetration. Snap Caps are color coded for easy sample identification. Patented GC Snap Top Caps™ were developed to handle the most volatile samples, providing an airtight seal to the vial. Simply snap on the cap and an evaporation-proof seal of a crimp cap is achieved.