The PSM-1 is a high quality 0-150 psi pressure gauge suitable for use with reverse osmosis systems (RO). This gauge comes complete with 1/4" push fit fittings that allow easy installation into your existing reverse osmosis system, provided a 1/4" hose is used. This pressure gauge is essential. the performance of your RO system. All RO membranes rely on a sufficient supply pressure (at least 3 bar pressure, preferably 4 bar). Low water pressure is one of the main causes of problems with reverse osmosis systems, as low pressure can cause the system to not work optimally. Low pressure can lead to low reject rates, low flow rates and higher higher higher TTS The use of a pressure gauge when using a booster pump is also recommended to ensure that the pressure is in the optimal range. With this pressure gauge, you can monitor the input pressure of your membrane and give a rough guide to when your pre-filters need to be replaced. Pressure gauge comes with two connections: QT-05 - T-piece, with 0.6 cm stem and two two 0.6 cm connectors.QT-15 - Female 1/4" direct to 1/4" plug-in connector.Diameter of gauge is 53mm, depth of gauge is 27mm, connection at base of gauge is brass, range: 0-10bar / 0-150psi.