4400 Heat Stress Stress Tracker - OrangeThe Kestrel 4400 Heat Stress Tracker detects when conditions are not safe, even before your body does. Kestrel"s 4400 measures wetbulb globe temperature, thermal work limit, naturally aspirated web bulb temperature, globe temperature and mean radiant temperature.Kestrel 4400 Accurately Measures:Barometric pressure Pressure trend Altitude Relative humidity Heat stress index Dewpoint Wet bulb temperature Density altitude Wind chillAir, water, and snow temperatureCurrent wind speedAverage wind speed Maximum wind gust