Reference pressures of -1 up to 1,000 bar can be generated in a fast and simple way by these pressure calibrators with high accuracy of measurement and compact type of construction. Exact adjustment of the desired pressure is carried out by a precision adjustment valve. The reference pressure is indicated via an analogue precision pressure gauge or a digital LCD. The instruments under test are connected to the pressure output of the calibrators by a pressure hose and an adapter. Power is supplied by batteries or rechargeable accumulators. The automatic measuring range switch of the PM series grants an optimal resolution with any application. Different measurement units can be selected by pressing a function key. Reference Gauges for Pressure Calibrator Series PM: All hand-held pressure pumps and reference gauges can be combined for different measuring ranges, resolutions and accuracy classes, as outlined below.