This product is a replacement part for the old style HF COSYS, and is not a complete unit/system.CO2 is an odorless, invisible, and non-flammable gas. The average level of CO2 in the atmosphere is about 300 ppmv (parts per million). If the level decreases down below 200 ppmv in an enclosed growing area, plant growth slows to a halt. Through the years of testing and research, the optimum enrichment level of CO2 for plant growth has been established at 1500 ppmv. With CO2 enrichment, under good conditions, plant growth rates and flowering will increase 20-100%. CO2 can be used from seedling right through harvest.