The CO2 DIY kit is with ABS engineering plastic cover, with locking pipe device to ensure non-deformation, non-loose, non-slip wire when working.And it's with professional metal material gas adjusting valve to ensure pure CO2 DIY According to the pressure principle,to push the acid liquid into the small soda liquid,the two liquids reacting to produce continuous PURE carbon dioxide This CO2 Generator System Kit is with Pressure gauge for pressure display,gas adjustable function,and simple pressure relief, easy to operate, safe and practical advantages! Once start, sustainable gas supply! Easy to operate and designed for low cost planted tank use,to provide your aquarium plants an abundant CO2 environment for better growing.