Ultrasonic: Essential oil will be cracked into smaller molecules and released into the air with 2.4mHZ ultrasonic; creating a non- smoke and safe mist area 7 Changing Light: 7 LED colors to match your mood, creating a fantasy surrounding; or staying with one color; or turning off the light 200ml: Hold 200ml water; produce mist 25ml/hour, work for 4-5 hours; ideal for a 10-20 ft2room Whisper-quite: Noise level < 35db(A), you won't be aware of the working diffuser when you are reading, sleeping, working or doing yoga Timer&Auto Shut-off: You could use 2/4 hours timer to turn it off; it will shut down if water runs out, giving you a worry-free operation