The PD200T is a high-flow sample dryer used in trace-gas analyzer systems for applications such as eddy covariance. It removes water vapor from the air sample before entering the analyzer, thereby eliminating water vapor absorption interference and eliminating the need for corrections to the trace-gas flux due to water vapor flux (i.e., eliminates the need for the WPL correction). The PD200T consists of a 200-tube, 48 in. Nafion® dryer element manufactured by Perma Pure, Inc., that is housed in a rugged dryer shell designed and manufactured by Campbell Scientific. The PD200T includes a filter holder, a flow meter to measure purge flow, needle valves to adjust the sample flow rate and purge flow rate, and mounting hardware.