Closure caps

A combination comprising a container, a closure plug and an overseal cap, the combination comprising:

• a container comprising an upstanding neck;
• a closure plug connected to the container, the closure plug comprising:
• a bottom wall;
• a sidewall configured to engage with the upstanding neck of the container;
• a plurality of lugs extending axially upward from the bottom wall, each of the plurality of lugs comprising a radially inwardly facing guide surface and a locking groove at the base of each lug;
• an overseal cap comprising:
• a cap top having a top surface and a bottom surface;
• and
• an attachment ring extending axially downward from the bottom surface of the cap top under a central portion of the cap top,
• wherein the attachment ring comprises a cam surface extending radially outward from the attachment ring, the cam surface being received within the locking groove at the base of each lug to securingly engage the attachment ring with the closure plug,
• wherein the cam surface is configured to deflect the attachment ring radially inward upon engagement of the attachment ring with the radially inwardly facing guide surface of the closure plug, and
• wherein the cap top and the attachment ring are connected by at least one frangible connection and at least one permanent connection, the at least one permanent connection being configured to retain the cap top and the attachment ring upon breaking of the at least one frangible connection.