The PMP-0.4 Low Pressure Test Pump is a hand-operated pressure pump designed to generate pressures from -0.4 bar to 0.4 bar. A high-quality screw press is designed for fine pressure adjustment, with an adjustment resolution up to 0.001 mbar. The PMP-0.4 is a very stable low pressure calibrator. Built with an isothermal bellows chamber, it is designed to reduce the possible effects of environmental temperature change. Most pumps are not well insulated which will cause large fluctuations at ambient temperature changes or when the unit is touched; this is not the case with the PMP-0.4. The two hand-tight connectors installed on the pump allow easy connecting and disconnecting by hand to measuring instruments, making the calibration work efficient and pleasant. The PMP-0.4 comparison pump is your essential tool for calibrating your very low pressure instruments.