Excellent diffuser essential oils, nothing to say but positive about it. However I still have some questions regarding the emission of negative ions (see description: "The diffuser also allows KEA mist cleaner air in your home and reduce environmental pollution through the issuance of negative ions "). Nor is there about this function negative ions (I already had an ionizer in the past) in the user manual. Why talk about this function not found to boast a mist that did not need and did its job perfectly diffuser / fogger also!