Natural Resources Institute Finland (hereafter referred to as "Luke") requests your tender for Open-path Ammonia (NH3) Gas Analyzer and Methane (CH4) + Nitrous Oxide (N2O) Analyzer with this Call for Tenders and its annexes. High precision and fast response Analyzer for Ammonia (NH3) and and Methane (CH4) + nitrous oxide (N2O) Analyzer in agriculture environments attached to existing Eddy Covariance equipment and used in Eddy Covariance Flux studies. Ammonia analyzer must function outdoors and both analyzers must provide a scientific accuracy and robustness for long-term environmental monitoring. Procurement is divided in two (2) lots: 1. Open-path analyzer for Ammonia (NH3) 2. Methane (CH4) + Nitrous Oxide (N2O) + Water Vapour (H2O) Analyzer One supplier is chosen for each lot. The subject of the procurement is described in more detail in procurement documents.