This product has been discontinued. Take a look at HD700 - Differential Pressure Manometer (2psi)
Extech PS101

PS101: Differential Pressure Manometer (1psi)

11 Measurement Units, High Resolution

Extech’s PS101 differential pressure manometer is ideal for field, manufacturing or lab/R&D use offering a 1psi range, readings in 11 units and high resolution. The manometer also features a large LCD display with backlighting, data hold, auto power off/disable and zero function for offset correction or measurement. This product is complete with 6 AAA batteries, two connection hoses and a hard carrying case.