ITEM NAME:Diy Aquarium Fish Tank Co2 System Generator Kit With Tubes Tool Part Bottle H6D9 Diy Aquarium Fish Tank Co2 System Generator Kit With Tubes Tool Part Bottle H6D9 Fish:Fish Tank CO2 System Generator co2:Aquarium co2 aquarium:co2 regulator co2 diffuser:Aquarium co2 CO2 system is designed for low cost planted tank use Easily set up/low cost/excellent quality Specifications: Inside diameter:Approx 27.5 mm For header pipe size: Outer diameter:6MM Inner diameter:4MM color:White material:plastic Package Contents: 2* Bottle Cap.Co2 aquarium:co2 regulator. co2 diffuser:Aquarium co2. Fish:Fish Tank CO2 System Generator. CO2 system is designed for low cost planted tank use. 2 Bottle Cap. Easily set up/low cost/excellent quality.