???? AUTOMATIC PRESSURE RELIEF: The safety valve automatically relieves pressure when the pressure in the bottle reaches 70kg/cm. It is safer and lighter with a new stainless steel gas cylinder. Do not invert the steel cylinder or tilt it. ???? CONTROL THE BUBBLE SPEED: You can use the fine-tuning valve to control the speed of the bubble according to the size of the home aquarium, thus controlling the carbon dioxide content in the aquarium to ensure healthy growth of the organisms in the aquarium. ???? PHOTOSYNTHESIS:A carbon dioxide generator with a solenoid valve can be used with the lights on the aquarium after the timer is installed. The combination of carbon dioxide and light will promote the crazy growth of water plants, so that your aquarium machine has an ornamental effect. ???? ACCESSORIES:This carbon dioxide generator kit includes: gas cylinder, solenoid valve, pressure relief valve, three-stage filter, fine-tuning valve, bubbler, diffuser , check valve, operating instructions. You only need to buy the corresponding raw materials. ???? INSTRUCTION:We will provide an operating video and operating instructions that will allow you to quickly become proficient in the use of this CO2 generator. If you are concerned about excessive carbon dioxide, you can monitor it in real time using a CO2 detector.Due to aviation restrictions, the packaging does not contain raw materials.