The Prisma ADT-901 low Pressure Test Pump is a hand operated pressure pump designed to generate pressure from -0.4 up to 0.4 bar. A resolution of 0,001 mbar is obtained thanks to its exceptionally high-quality and fine adjustment valve. The ADT-901 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. The ADT-901does 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 ADT-901 is an ideal comparison test pump for low pressure applications.