A tiny bit technical today with the constitution of the cork aiming at sealing a bottle of champagne.
Indeed champagne cork must have very specific qualities to resist a pressure of 6 kg/cm2, which is almost three times the average pressure found in car tires. The top part is made of agglomerated cork to ensure resistance to torsion, when the bottom part that is in contact with the wine, known as mirror, consist of natural cork in the form of one, two or three pellets, each 6 mm wide. On the top of that champagne cork is nearly as wide as long : 31mm to 48mm.
Finally the word "Champagne" have to be written on it.
