A ring-pull is the metal ring or tab on the top of a drinks can that the consumer pulls to open it. Introduced to replace the separate church-key opener, it evolved from the detachable pull-tabs of the 1960s, which littered beaches and caused injuries, into the stay-on tab used today, where the tab stays attached to the lid and levers a scored panel inward. The mechanism must open reliably with a light pull while keeping the can hermetically sealed through filling, pasteurisation, transport, and stacking. Can makers engineer the score depth precisely: too deep and the seal fails, too shallow and the tab tears off. It is a small piece of packaging design that billions of people operate without a thought.