The calibration unit OZGU-370SE is designed for the dynamic and continual manufacture of zero and span gas to perform all ongoing quality control procedures according EN 14625. Transfer-standard OZGU-370SE is based on well proven Analyzer APOA-370 with integrated span gas generation unit (ASGU-370 Electronic). This Span gas unit is able to provide ozone gas to an 2nd Ozone monitor. The actual concentration is measured by the type approved measurement cell of the transfer standard.