Features:This CO2 aquarium regulator can assist your water plants in their growth cycle.Always inject the right amount at the right time to keep your plants growing the right way.With 2 dual display allows for easy reading of your settings to ensure that they are always where you want them to be.The precision construction of this regulator will ensure that you can always fine tune the amount of CO2.Perfect CO2 aquarium regulator to create the best growing conditions for your aquarium plants. Specification:Material: Stainless steel + Aluminum alloyColor: SilverSuitable interface: G5/8, W21.8(Optional)Size: 12.5*12*7.5cm / 4.9*4.7*2.9 inch(Approx.Package list:1 x CO2 aquarium regulatorNote: The product is a model without a magnet. The outer diameter of the G5/8 steel cylinder is about 22.2-22.5 mm, and the W21.8 steel cylinder thread interface is 21.8-21.6 mm. The outer diameter of the G5/8 is 22.911, with 14 threads per inch, and a pitch of 1.814 mm..