This safety orange Kestrel 5400 Heat Stress Tracker with LiNK and vane mount measures wet bulb globe temperature, thermal work limit, heat index temperature, humidity, and humidity. The natural wet bulb temperature is calculated from on-board digital sensors and does not require water. LiNK technology provides wireless communication to mobile devices and computers. Kestrel 5400 Safety Orange Heat Stress Tracker Pro 0854LVCORA