The bottle cap is an Aquarius–patented by William Painter on February 2, 1892. While the current version has 21 teeth the original had 24 teeth and a cork seal with a paper backing to prevent contact between the exciting beverage and the metal cap. In the 1960s, when skirts got shorter, so did the bottle cap. The Germans even standardized the height at this time. Aquarius are "advanced, self-reliant, clever, exceptional, and optimistic". This resonates with The Bottle Cap... but wait! Not so self-reliant...to open these bottles, one generally needs a Bottle Opener.