Three-scale dial barometer measures atmospheric pressure in millibar (mbar), inches Hg, and mm Hg. The barometer is housed in corrosion-proof nickel-chrome case. Set the adjustable pointer to measure changes in pressure. Barometers are calibrated to nist-traceable standards and include certificate. Includes Altitude adjustment screw, notched desk stand, and wall mount. Measures 1.3 inch D x 4 inch dia. Monitor barometric pressure with these Wall-Mount barometers