I purchased this air system, about 3 months ago, and what can I say , one of the best buys I have every made,, almost immediately you can feel the difference... Especially for me who has always had respiratory issues,,, FINAL I CAN BREATHE AGAIN.... I can say that this product is of high quality, I even bought one for my Mom and sister who has two lil kids... I have two units and if I had more money I would buy more... Thanks Neoair for putting out such a great product!!!!!!!!!!