The XL ExHale CO2 Bag is a simple, inexpensive way to add CO2 to your growing area. It contains a mycelial mass inside a vented bag that produces and releases Co2 continuously for at least 6 months. On average will raise the CO2 level by 500ppm above the ambient air level. It is ideal for medium to large sized growing spaces. This bag will provide a 6’x6’ or 288 cubic foot space with CO2 for 6 months guaranteed.