GASCO Nitric Oxide Calibration Gas/NO calibration gas, also known as Cal Gas, is used for the Calibration and Maintenance of Gas Detectors and Sensors. GASCO Calibration Gas Cylinders ship with a COA (Certificate of Analysis). GASCO Calibration Gas meets or exceeds the requirements of the Original Gas Detection Equipment Manufactures Specifications. GASCO Calibration Gas is National Institute of Standards and Technology (NIST) Traceable and Made in the USA.