The He enters the cryostat at a pressure of a few hundred millibar. This system had a pressure of 970 millibar at one point. The core of the sodium line runs from pressures of 50 millibar to a microbar. Atmospheric pressures are usually stated using hectopascal (hPa), kilopascal (kPa), millibar (mbar) or atmospheres (atm). It featured low millibar heights roughly four times below the standard mean.