choice of making CO2 equipment at home. It is easy, safe and economical. Raw material ratio: A bottle: Citric acid 200g'water 600g; B bottle: Baking soda 200g'water 200g. Specification: Name: DIY CO2 generator system Main material: Aluminum alloy Main color: Silver 3 type optional: CO2 generator system/CO2 generator system'bubble counter with check valve/CO2 generator system'bubble counter with check valve'solenoid Raw material ratio: A bottle: Citric acid 200g'water 600g B bottle: Baking soda 200g'water 200g Note: 1. The package does not contain containers for reaction raw materials. Please prepare 2* 1.5L or large plastic beverage bottles (coke plastic bottles are the best). Do not use bottles or beer bottles to avoid bottle accidentally cracking or exploding due to excessive pressure in the bottle. 2. Boost pressure operation: If the pressure gauge shows that the pressure is too low to reach 1KG, the boost pressure operation is required. Customer needs to open the trim valve to release the gas, then close the trim valve and shake the bottle (the AB bottle is shaken together) on order to react the raw materials faster. Repeat the operation, and then observe the pressure until the pressure rising. If the pressure achieve the ideal pressure you could stop the operation. The best starting pressure is 1KG. 3. Don't open bottle directly when there's still on pressure, please wait for its automatic pressure release. Package Information: Package size: 22 * 12 * 6cm Package weight: 333g Gift Box Packaging Package List: 1* CO2 generator system 1* Pressure gauge 1* Safety valve 1* Fine adjusting valve 1* 1.5m tube 2* Suction cup 1* Manual