Traceable precision barometer's triple scales provide a sensitive measure of atmospheric pressure from 954 to 1073 millibars, 28.1" to 31.7" of mercury, and 715mm to 805mm of mercury with a resolution of 0.5 mbar, 0.05 InHg, and 0.5 mmHg. Accuracy is +/-0.5 percent of reading. To assure accuracy an individually serial-numbered Traceable certificate is provided from our ISO 17025 calibration laboratory accredited by A2LA. It indicates traceability to standards provided by NIST (National Institute of Standards and Technology). Housing is rugged corrosion-proof, nickel-chrome. Adjustable pointer may be set to indicate changes. Complete with altitude adjustment screw (use at locations as high as 1000 meters), notched desk stand, and wall mount. Measures 4-1/8" diameter by 1.5" thick. Weight is 1 pound.