The Dwyer MARK II WSI-NIST Wind speed indicator, MPH scale, with NIST indicates wind speed directly on its liquid filled scale reading in both miles per hour (0-80) and Beaufort scale (1-12). The MARKIIWSINIST instrument is 100% pneumatic, operating on the time proven principle of aircraft speed indicators. The MARKIIWSINIST consists of a pickup vane connected by fifty feet of flexible double column tubing to the Mark II Indicator, plus all necessary mounting hardware, fluid, and instructions. In operation, wind aligns the MarkIIWSINIST weathervane pointing the pickup tube into the wind. Wind pressure enters and is transmitted through plastic connecting tubing to red fluid inside the indicator. Fluid level rises and falls in response to changing wind speed. Scale calibrations on the Mark IIWSINIST indicator show the wind speed corresponding to various fluid levels. For wind direction, observe the weathervane position.