The differential pressure measuring instrument GBA 604 comes in a plastic housing and is ready for connection. It is designed for surface mounting. The GBA 604 is especially suited to control pressure differentials of filters used in cleanroom and climate technology. The GBA 604 instrument features a high reading accuracy and repeatability. They can be used in negative pressure and/or overpressure conditions. It can be mounted on a surface of a wall or a housing of an air-conditioning device. The GBA 604 combines an analogue differential pressure gauge of the Magnehelic series 2000/2300 and a pressure transmitter. It is very accurate and resistant to over-pressure. As the analogue display works without any measuring liquids, it is maintenance-free and also resistant to over-pressure. At the output of the differential pressure transmitter, a signal of 4–20 mA or 0–10 V is produced for further external processing and continuous monitoring of the filter pressure. To ensure a reliable performance, only high-quality components are used.