The Additel ADT912AB Low Pressure Test Pump, 60 psi, 1/4 BSP (F) - Air is a hand operated pressure pump designed to generate pressure from 95% vacuum to 60 psi (4 bar). A high-quality screw press is designed for fine pressure adjustment, with an adjustment resolution up to 0.1 Pa (0.001 mbar). The ADT912A-B is a very stable low pressure calibrator. It makes use of an isothermal bellows chamber which is designed for reducing the possible effects of environmental temperature change. Most pumps make use of a check valve (non-returning valve) and are not well insulated which will cause large fluctuations in pressure with a change in ambient temperature or when the unit is touched. The ADT912A-B does not use a check valve and is remarkably stable. Two hand-tight connectors installed on the pump allow easy connecting and disconnecting to the test pump without the need for PTFE tape or wrenches. The ADT912A-B is an ideal comparison test pump for low pressure application.