Reads wind speed in miles/hour, meters/second, and Beaufort. Readout dial is supported on sapphire jewel bearings and steadied by a rare earth magnetic dampening system. Folding handle quickly and securely latches into place. No batteries needed. Dimensions: 3-5/8 2-7/8 1 (92 73 25 mm) with handle folded. Weight: 2.5 oz (71 g). Measures wind speed from 0 - 60 mph.