The CPEC310 with EasyFlux® is a turn-key, closed-path eddy-covariance (EC) flux system for long-term monitoring of atmospheric-biosphere exchanges of carbon dioxide, water vapor, heat, and momentum. A complete system consists of a closed-path gas analyzer (EC155 closed-path gas analyzer), sonic anemometer (CSAT3A sonic anemometer), data logger (CR6 datalogger), sample pump, three-valve module that enables automatic zero and CO2 span measurements (manual H2O span), and accommodations for a CDM-A116 analog input expansion module allowing for additional sensors. The gas analyzer’s patented vortex intake design (United States Patent No. 9,217,692) and small sample cell volume (5.9 mL) provide a much lower flow rate than other closed-path systems while maintaining excellent frequency response (4.3 Hz cutoff frequency). Additionally, this design makes the system virtually maintenance free while still maintaining an ideal frequency response compared to traditional inline filters. Lower flow allows the CPEC310 to have one of the lowest total system power requirements (12 W) of any closed-path eddy covariance system. Campbell Scientific manufactures all components of the CPEC310, including the data logger and EasyFlux® DL software for computing and correcting fluxes, which gives our system the most reliable functionality.