Each bag will suit a small to medium sized area & will last approximately 6 months. They will turn white with mycellium as they grow and just need some warmth to startup.   How Do CO2 Breathe Bags Work? Breathe bags create Carbon Dioxide (CO2) 24 hours a day with no need to refill bottles or use expensive CO2 production units. The power of these breathe bags lie in the mycelial mass inside the vented cultivator. This mycelial mass cultivates CO2 and the microporous breather patch releases CO2 continually for up to 6 months.   CO2 Breathe Bags Benefits Great for bumping up the CO2 in your hydroponic or greenhouse setup. Rated to support 2-4 plants for up to 6 months CO2 Breathe Bags Instructions Very simply place the bag in the required area and the Co2 will emit through the filter. (no need to open the bag or do anything else. Made from Australian materials and fungal matter.