brand new and high quality Features: 1.This CO2 bottle cap is suitable for most kinds of DIY reactor 2.Easy to use. Just screw the bottle cap on the drink bottle. Easy and sealed without letting the air out easily 3.Plastic material makes this bottle cap uneasy to rust and safe for your fish and water plant 4.For people who love DIY CO2 setup, this bottle cap is a helper when they are doing the process of generating CO2 5.If the water plant in your fish for tank/aquarium is growing slowly and needs more CO2, this bottle cap may help you 6.With the 2 holes, you can add both tube and other tool like bubble counter or other things to help you know and control the process CO2 Reactor Bottle Cap only,other accessories demo in the picture is not included. Specification: Material: ABS Diameter: app.3.3cm/1.30in Optional Color: Blue, Gray White, Red Quantity: 1 Pc Note: No retail package. Please allow 0-1cm error due to manual measurement. pls make sure you do not mind before you bid. Due to the difference between different monitors, the picture may not reflect the actual color of the item. Thank you! Package Contents: 1 x CO2 Reactor Bottle Cap