Wheaton Unlined Aluminum Seals with Center Disc Tear-Out are available to fit two different vial sizes. The two sizes are: 13mm vials and 20 mm vials. The seals come in cases of 1000 each. They are not designed for use in extremely harsh conditions (i.e. high heat, etc.).
The seals feature a center disk tear-out. Users can use their finger nail to remove the center of the seal. The rubber stopper/septa underneath is exposed. They can then puncture the stopper/with a needle.