Mini 20 grams kit: - Ideal for small planted aquariums up to 57L/15 US Gal. - 20 gram cylinder will supply 55 refills of CO2 reservoir/diffuser - Simple to install and use - Regulator valve effectively controls CO2 output - Bracket secures CO2 cartridge to the side of the aquarium - Kit includes: regulator valve, cartridge bracket, disposable CO2 cartridge, hose, and internal CO2 diffuser