Vial Caps & Seals are available with a wide variety of septa & liners. Aluminum crimp seals have a larger opening to provide increased target area for needle penetration. Poly Crimp™ Seals permit an airtight seal by hand or use a standard crimping tool. 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.