The Hydor aquarium CO2 systems are the easiest to to set up and easiest to maintain CO2 systems on the market. Everything except for a Hydor NRG CO2 Disposable Cartridge is included in the packageFeatures:Does not include the CO2 cartridge. We recommend the Hydor NRG CO2 Disposable Cartridge. For aquariums up to 132 gallons Turbo Diffuser increases CO2 efficiency by 40% (compared to a normal CO2 diffuser)High and low pressure gauges for perfect controlHigh precision pressure reducer for CO2 rechargeable cartridgesSpecial glass bubble counter for perfect visibility, regulation and control.