Full-featured safety regulator with independent needle valve. Designed specifically for aquariums use, the Pressure Regulator and Needle Valve are independent units connected by low-pressure CO2 tubing. The high precision needle valve is designed to be mounted on the side of the aquariums 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 or under the aquarium. Easily upgradeable for automatic control with an in-line solenoid control valve. Easy to read high and low pressure gauges, integral pressure relief valve, independent, needle valve – stable flow rates from 4 bubbles per minute.