Air Box 4+, Stealth Edition (12")Air Box 4+ is a perfect solution to eliminate the nasty smell of manure or chemicals from your grow space. It consists of a heavy duty air box that helps you get rid of the odor for at least 18 months. Furthermore, it is very easy to maintain because you need to change the carbon filters yearly to ensure efficient functioning. Doing this will allow you to enhance your device's life. With this odor elimination device, you'll breathe in fresh air