This p-wave easy fresh intelligent air freshener system with a mango fragrance that gradually dispenses over 30 days has a unique design that allows air flow created by door movements to carry the fragrance around the room. it is a low cost system with a replaceable cover and lifetime guarantee on brain battery. to indicate that the cover needs replacement a light flashes on the unit on day 30, and then an audible beep is given on day 34. they are easy to install and the replaceable covers are fully recyclable. Less