the wireless frient Air Quality Sensor monitors the level of organic chemicals, humidity and air temperature in the room. It also warns you if the indoor air quality gets bad. Are you afraid of mold? The frient Air Quality Sensor measures the humidity in your rooms and warns you in time to prevent mold growing. But that's not all: The frient Air Quality Sensor also detects when the humidity is too low. So you are also alerted to prevent dry eyes and allergies that come along with it.