For years, indoor gardeners have trusted ExHale CO2 as their go-to source for all-natural CO2. ExHale Bags provide CO2 with no need to refill bottles or the use of expensive CO2 production units. They can be used for both vegetative plant growth, as well as for fruit and flower production. Used by growers worldwide, the Original CO2 Bag is suitable for 128 cubic feet of garden space, while the XL ExHale CO2 Bag will cover up to 288 cubic feet. Both the Original and the XL will provide CO2 for a minimum of six months guaranteed. For larger spaces, simply add more bags. For starting cuttings, the ExHale Micro is perfect for the standard clone dome and will provide CO2 for three months, guaranteed. Maintenance free, no heat, no electricity; just CO2.