The Physikalisch-Technische Bundesanstalt (PTB, Physical-Technical Bureau) is the National Institute of Metrology in Germany. The unit of pressure is realized in two PTB laboratories, in the laboratory  for pressure from 1kPa up to 1Gpa, in the laboratory for vacuum metrology for 10 ^–10 Pa to 1 kpa. In total 5 primary standards serve for the calibration of vacuum gauges as secondary standards. A mercury manometer from 100 kpa down to 1kpa, two static expansion systems from 1kpa down to 10 ^–2 Pa and 10^-6 Pa, respectively, and  two continuous expansion systems from 10^-2 Pa down  to 10 ^–10 Pa. The secondary standards for vacuum are used as reference standards in 6 laboratories of the German Calibration Service to disseminate the pressure scale.