Bottle Opener

A Bottle Opener is a device that enables the removal of metal bottle caps from bottles. More generally, it might be thought to include corkscrews used to remove cork or plastic stoppers from wine bottles.

A metal bottle cap is affixed to the rim of the neck of a bottle by being pleated or ruffled around the rim. A bottle opener is a specialized lever inserted beneath the pleated metalwork, which uses a point on the bottle cap as a fulcrum on which to pivot.

source: wikipedia