Measures current, maximum windspeed, current temperature, windchill, relative humidity and dewpoint. Choose any measurement unit. Replaceable 400 hour lithium battery. Data hold to freeze most recent display. Reads in tenths. Replaceable plastic impeller won’t corrode. Average windspeed over 5, 10, or 13 seconds. Unique pocket-knife design to protect unit when not in use. Optional Units: Knots, MPH, KPH, M/Sec, Ft/Min, Beaufort Scale – F or C. Auto shutoff 20 minutes after last key is pressed. Dimensions: 5.25″ x 2.75″ x 0.75″. Threaded for tripod mounting. Has a high visibility case.