At the heart of the Quick Lid is a segmented elastic ring.When open, the ring loosens and withdraws into the groove. The cover can be lifted off without an effort.

To close the lid, the ring is tightened by tilting a lever (not shown). It clings to the pressure vessel and a step in the vessel wall prevents the lid from being lifted off.

When pressure is applied to the vessel, it lifts the cover and wedges the ring between the vessel and the cover. The higher the pressure, the higher the closing forces. Unlocking the closure under pressure is therefore impossible.