Package Include: 1 x CO2 Splitter; Size: 10 x 7.5cm. For 4mm/6mm air hose tubing. For CO2 tank use. Good for aquarium plants. Easy setup, no modification required to your CO2 regulator. Each outlet is equipped with a separate needle valve, which can accurately adjust the CO2 flow. With this splitter, you can connect up to three CO2 diffusers/supplies from a single CO2 cylinder.