Closure part for a barrel (glass, rubber, wood, ceramic, plastic, silicone), which is inserted into the bunghole. In order to let gas escape or to allow ventilation, the bung can also be inserted loosely or it has a corresponding device (valve) that allows this in one direction only. This is also called fermenting bung (see fermenting attachment). In this case the barrel is stored in such a way that the bunghole is at the top. If one wants to achieve during the barrel removal that no ventilation can take place, then the barrel is turned so that the (in this case firmly closed) bunghole is below the liquid level. This position is called the "two o'clock" position. The advantage is that the empty space formed by evaporation is formed on the smooth inner wall of the barrel. On the other hand, a "12 o'clock position" can lead to leaks, especially in wooden pegs, because they can dry out in the air bubble. There is thus a risk of oxidation and also of larger-scale shrinkage.