Pressure gauges, pressure measuring apparatuses, electronic pressure sensors, pressure recorders, pressure transmitters, and pressure indicators, in particular those with digital displays; pressure gauges, pressure measuring apparatuses, electronic pressure sensors, pressure recorders, pressure transmitters, and pressure indicators for measuring and/or recording barometric pressures for weather forecasting, altitude measurement and scientific research; pressure gauges, pressure measuring apparatuses, electronic pressure sensors, pressure recorders, pressure transmitters, and pressure indicators for measuring negative pressure or vacuum conditions; pressure gauges, pressure measuring apparatuses, electronic pressure sensors, pressure recorders, pressure transmitters, and pressure indicators measuring pressure and temperature; electronic devices that display pressure and/or temperature values and further offering at least one additional function, for example data recording, switching-functions, alarm-functions, wireless transmission of data, wired output of digital signals and/or wired output of analog signals; electronic devices for measuring the pressure difference between two points; electronic devices for monitoring air filters; electronic devices for measuring flow velocity of gases and liquids; electronic devices for measuring the liquid pressure determined by the height of a liquid column above a measuring point.