1) The ICOS labeling process involves regular data checks between the central lab and station PIs to evaluate performance and ensure quality standards. This includes examining calibration stability, stabilization times, inlet integrity, and identifying/solving any issues. 2) The initial tests at 11 stations found calibration gases usually stabilize quickly except for CO2 and CH4, which require drier conditions. Tests also identified problems at two stations that were later resolved. 3) Through collaborative review of station data and testing, the labeling process aims to optimize operations and deliver harmonized, high-quality greenhouse gas measurements across the ICOS network.