The Micro-Cal Model 869 has been specifically designed for air handling processes in critical environments that require portable, high accuracy and low-pressure documenting calibration to certify pressure needs. The Model 869 provides this capability by performing calibration checks on sensors with accuracies as high as .00025 in. W.C. The new Micro-Cal was engineered to be portable, lightweight and compact for use in cramped or remote locations. This battery-powered unit provides a minimum of 8 hours of operation, while giving a pressure reading accuracy close to .0001 in. W.C, with fast, stable and repeatable pressure generation better than .0003 in. W.C. Additional features include a removable process head, which increases ease-of-use by eliminating the need to cut tubes, and a detachable terminal block, so field wiring can remain in-situ during calibration.