The EC6 Strain Gauge and Photo Plethysmograph is accurate and easy to use for a wide variety of measurement applications. The EC6 is most commonly used to measure arterial inflow, and maximum venous outflow. Strain gauge plethysmography is the standard mode for testing endothelial dysfunction and reactive hyperemia. Its features include AC and DC coupling, seven range settings, adjustable analog output for use with an external chart recorder, and a built-in RS232 data output. The RS232 data output is ideal for communication with the Hokanson NIVP3 Software for waveform capture and storage. When used for arterial inflow a possible contraindication is previous DVT.