This needle valve is with 1/8 NPT male thread.
CO2 Needle Valve is used for precision control of the flow of CO2 gas, which is not possible by use of the regulator alone. The bubbles should be fine tuned so that they are VERY SMALL and rise slowly and lazily to the top of tank, but almost become absorbed about 1-2 inches before reaching the surface. This way maximum use of the CO2 gas is achieved.
This co2 needle valve is manufactured to the highest standards possible. The unit is a miniature precision needle valve, for sensitive and repeatable control of gases such as CO2.The CO2 Needle Valve can give precise control of CO2 gas when installed as directed, thus enabling the optimum use of CO2 gas in the aquarium.