Skymate Plus has all the wind features of the SM-18 plus an accurate hygrometer for relative humidity and dew point. The Honeywell humidity sensor is easily recalibrated. The SkyMate Plus is a competitively priced instrument designed for agriculture and forestry professionals. For the most precise measurements, it can be used with the optional wind tunnel, Model SM-WT; or tripod mounted using the optional tripod mounting fixture. SM-19 wind meters are designed with a wind speed accuracy of better than +/- 3% and have a 2-Year warranty.