I love my new Essential Oil Diffuser, 250ml Ultrasonic.
Aromatherapy mist brings calm and relaxation and the large tank in 250mL unit promises a long cycle. I didn't feel like it lasted as long as another one I have. The opening is pretty small. The top dome comes off to fill up with water. I put in peppermint oil in ours. You may also use it without essential oil to humidify the local air, where it may improve breathing and reduce nasal congestion.
The unit operates with a small switching power adapter that plugs into a nearby receptacle (6-foot cord).
Neither heat nor noise is produced. Only a gentle hum may be heard, indiscernible in most ambient locations. It does have a beep when it's done.
There is a low setting and a high setting. On low setting I could not see the steam come out until I saw the photos.
I think diffusers are great for anyone with allergies, asthma, or any type of cold/sickness. It helps break up a cough.
Disclaimer: I received this diffuser at a discount for the purpose of this review. The opinions are 100% mine.