Whisper-Quiet Ultrasonic Operation Adopted advanced ultrasonic technology?? this essential oil diffuser is extremely quiet without annoying noise that won't disturb you when you sleep or at work.</br>Auto Shut-Off function Gives you peace of mind when using the diffuser?? as when it is detected that there is no more water or water runs out?? the diffuser will automatically power off for safety insurance.</br>Mood-Enhancing Lights With 7 soothing LED light?? you can cycle through it or freeze it on one fixed color. The brightness is selectable from dim and brighter.