1.Ultra-Quiet Design: The mini ultrasonic humidifier uses the power of ultrasonic vibration to turn water into a cool moisturizing mist, generating a nearly silent frequency of 25dB (quieter than the library). This usb humidifier can effectively moisturize dry skin and provide a quiet and comfortable sleeping environment. 2.Two Spray Modes and Auto Shut-Off Protection: This portable humidifiers has mist modes: continuous mode and intermittent mode. when you click the function button first time, it will continuously spray for 4 hours; When you press again and it will intermittently spray (stop 3 seconds) for 8 hours. It will shut-off when the water level is low. Thus, you don't have to worry about the desk humidifier being damaged in the absence of water. You can use it at night without worrying about safety. 3.Portable Cute Small Humidifiers : This personal humidifier(240 ml)is convenient for small spaces, such as be used as air humidifier for home, office, car, living room, office, bedroom or driving travel. The USB Power Supply compatible with any device USB port which ensures it can be used in bedroom, office, car. 4.Vivid Colorful Cycling Light: For the first time, press the button for 3 s, then the cool mist humidifier turn on the VIVID colorful light, creating a dreamlike atmosphere. Also, you can fixed the color you like by pressing the button again.