BEWARE! Customer Service is non existent if product fails.
Please be aware that customer service isnon existent! If your product stops working, you will never hear back from them via email. If you do call the US number, the woman speaks minimal English and will not be able to help you with your issue e.g. sending me a return label for an exchange. I wasted $600 on a face mask that is useless as this point. Choose other face mask companies with better reviews and quality or else you could waste hundreds of dollars like I did!