High Accuracy & Quick Refresh Rate: HT-21 features high accuracy of ±23%RH and ±1°F, which makes it ideal for any indoor spaces. Data measurements are updated every 10 seconds to provide latest update on your environment. Air Comfort Indicator: Humidity level indicator shows the current air conditions from Dry, Comfort, Wet to provide current and changes in air condition in your indoor environment/room with just a look Max & Min Records: You can see High and Low readings for both temperature and humidity level for the past 24 hours or All time (From the moment the device is turned on) 3 Level nightlight brightness: You can adjust brightness of the nightlight to get the perfect light setting in the dark Portable Toddler Night Light: You can use the stand as a handle to carry the nightlight with you. Now you don't have to buy a hygrometer and nightlight separately Bright back light: Bright back light helps to see the screen clearly in the dark. Rechargeable: With 90 minutes of ch