The Bio-CO2 Pro system combines the safety of biological carbon dioxide production with the convenience of pressurized delivery. Offering simplicity and unparalleled performance in an easy-to-use format, Bio-CO2 delivers reliable and controllable CO2 through the naturally occurring fermentation process. With safe, low-pressure operation, it is the most secure, simple, and environmentally-friendly aquarium CO2 delivery system available. -Easy-to-use CO2 delivery system allows both new and experienced hobbyists to effortlessly grow and maintain vibrant live aquatic plants-Safe low-pressure operation - 1.3 bar / 19 psi max. vs. traditional high-pressurized systems (55-80 bar / 800-1100 psi)-Provides up to 30 days of reliable CO2 production through a naturally occurring fermentation process involving sustainable raw materials (sugar and yeast)-Recharging convenience – no refilling high-pressure cylinders-Quick 4-step process requires less than 10 minutes per month to maintain-High-quality stainless steel reaction chamber with 100% silicone gasket prevents CO2 escape-Adjustable bubble counter with precision regulator and nano bubble diffuser for accurate CO2 delivery-Pressure release valve for additional security and peace of mind-Starter Bio- CO2 Activator yeast and Booster tablets included – Refill Packs sold separately (#A8457)-System is compatible with CO2 level tests (sold separately)-Developed in Germany Included: -Stainless-Steel Reaction Chamber-Adjustable bubble counter with precision regulator-Nano Bubble Diffuser-Pressure Release Valve-Inline Check Valve-Gasket x 2-Airline with gas barrier (5 ft / 1.5 m)-Activator packet x 1-Booster packet x 1