The pressure reducer performs three functions: with the central knob opens the gas and adjusts the output pressure with the knob for fine adjustment adjusts the flow rate, providing the right amount of co2 for each aquarium, with the pressure gauges allows the control of the pressure inside the cylinder and the outgoing one. Precision reducer with self-regulating system – allows precise and constant gas delivery over time. Knob for fine adjustment – the processing of this component is very accurate so that you can accurately adjust the output of carbon dioxide even for a few bubbles per minute. Central knob – allows you to adjust the gas pressure and open and close the system without changing the precision adjustment already set. The plants at night do not perform photosynthesis and do not consume co2; if you continue to enter carbon dioxide, this would add to the breathing of fish and plants. As well as being a useless waste, it could cause intoxication and changes of ph. Only with our pressure reducer, equipped with the on-off knob, the night suspension can be done manually and without touching the fine adjustment set. Safety; internal safety valve – occurs in case of an abnormal increase in pressure within the reducer. Hose connection with hose clamps – the fitting conformation prevents gas leakage. Practical standardised measurements for the hose and for attaching to the cylinder – you can find the hose and the bottle at an affordable and uniform prices. Brass body with nickel-plated outer – protects the product over time.