A flip-top, swing-top, lightning toggle, or Quillfeldt stopper (after the inventor, Charles de Quillfeldt) is a type of bail closure frequently used for bottles containing carbonated beverages, such as beer or mineral water. The mouth of the bottle is sealed by a stopper, usually made of porcelain or plastic, fitted with a rubber gasket and held in place by a permanently attached wire bail. The bottle can be opened and resealed repeatedly without the use of a bottle opener, with the wires acting in the same way as a latch clamp. The flip-top was the dominant method of sealing beer and mineral water bottles prior to the invention of the crown cork.