Yosoo DIY Co2 System Kit D201 Tube Valve Guage Bottle Cap for Aquarium Moss Plant High Quality: 100% brand new, high quality, non-toxic, Eco-friendly and durable to use. Easy to Set Up: Easy operations, great DIY enjoyment, perfect CO2 generator. Energy Saving: CO2 system is designed for low cost planted tank use. Great Design: Trimming valve regulation avoid by sudden big or small, can't suddenly turn up, after immediately shut down again, so as not to cause abnormal pressure to the bottle. Note: Make sure carefully observe the direction of the parts before assembly. The usual wrong handle way will cause abnormal reaction components as follow: the contrary direction of the check valve and fine-tuning in the direct. easy to set up