The laboratory has a standard gas generator, which allows wet and dry air to be mixed to obtain COFRAC traceable national humidity references. Both types of air are continuously generated with a constant flow, and are constantly checked in terms of dew point/frost temperature. The generation ranges of standard dry and wet gases range from -100°C to +20°C dew point/frost, at ambient temperature and pressure. These beaches are certified using a five-stage cooled mirror hygrometer, cooled by a water source, and calibrated at International NPL lab. This laboratory allows Gruter & Marchand  to issue calibration certificates, which are traceable to the COFRAC national humidity reference. Gruter & Marchand does allow have a lot of certified cylinder gases with mixing station to do calibration in ppm and percentage for O2-CO2-CO-NO-H2-CH4-SF6-…