The Dwyer HM28D3B10000 Handheld Digital Manometer 0-10 in w.c., 2-Line LCD Display is a digital pressure measuring instrument with integrated pressure sensor for the measurement of differential or relative pressures. Features include: measurement in all common pressure ranges, display resolution to 0.001, differential or relative measurement, two line liquid crystal display, and adjustable auto power off to conserve battery. The HM28D3B1000 records up to 964 readings and offers up to .05% accuracy.