Do you want to make CO2 yourself for your fish tank? This kit will be a good choice. It is easy, safe to operate and can create CO2 constantly by the reaction of citric acid and soda. With it, you can make CO2 at home conveniently. Features: Fully installed, direct to use and labor-saving. Well-sealed caps & pipes, leak-proof, non-deformed, never loose. Professional pressure guage for safe-area indication, pressure watching. Decompression automatically for safer usage and operation. Cheap, simple to create pure CO2 constantly by chemical reactions. With adjustble air flow vavle to control CO2 volume easily. Note: 1.Don't open bottle directly when there's still on pressure, please wait for its automatic pressure release. 2.Please use food-grade citric acid and baking soda as the raw material. 3. For more specific instructions and usage, please read our English user manual. 4.The initial set of safety vavle is 4kg/c , you can also adjust it manually. Specifications: PU Connecting Pipe Lenght: 160cm / 62.99in Item Weight: 300g Package Size: 18.5 * 13 * 4.5cm Package Weight: 400g Package List: 1 * CO2 Generator Kit 1 * English User Manua