CO2 Regulator with dual gauges and independent Needle Valve for regular CO2 cylinders, Red Sea. Designed specifically for aquarium use, the Pressure Regulator and Needle Valve are independent units connected by low-pressure CO2 tubing. The high precision fine-flow needle valve is designed to be mounted on the side of the aquarium enabling easy access for regular flow adjustment or complete shut off. Once assembled and set to the desired working pressure the CO2 Cylinder/Regulator can be located out of site, behind the aquarium. Independent needle valve allows for stable flow rates of CO2 as low as 4 bubbles per minute.