Why Glass?
It is important to realize that while pure essential oils are 100% natural (with nothing chemical or man-made added), over time they are corrosive to plastic. You must not put essential oils in prolonged contact with anything plastic.
Eventually, plastic will be dissolved and harmful, potentially carcinogenic particles from the plastic may find their way into your essential oil, making them dangerous when diffused. Always use materials made from glass to store and to diffuse essential oils.

Whisper Quiet
Organic Aromas nebulizing essential oil diffusers are whisper quiet. With your ear placed right next to the unit you should hear a slight humming sound. Even then, the sound will be so soft it is virtually non-existent.
Their silence makes a perfect addition to your home, spa, office classroom, kitchen or elsewhere as this diffuser is commonly used by health professionals, counselors, therapists, aestheticians and kinesiologists.If you want to put it in your bedroom, you had better turn down its output when you are sleeping, so that its voice will be almost inaudible.