Used where precise temperature measurements are critical. Filled with nitrogen above mercury. Factory-certified against NIST-certified standards and furnished with calibration certificate containing correction to the nearest one tenth of smallest scale division. Traceability to NIST. Recommended to be used to verify and calibrate instruments. A felt-lined, leatherette case is provided with each thermometer for safe storage. 9295N50 through N66 are calibrated for 76 mm immersion; 9294N70 through N80 for total immersion. Nitrogen-topped, yellow background.