Jardin Outlet Compact Clear Glass CO2 Diffuser for Aquarium, 20mm Product Name : Aquarium CO2 Diffuser; Use for : Aquarium, Fish Tank Color : Clear; Material : Glass Inlet Diameter : 4mm/0.16"; Outlet Diameter : 20mm/0.8" Overall Size : 63 x 30 x 20mm/2.5" x 1.2" x 0.8"(L x W x T); Net Weight : 12g Package Contents : 1 x Aquarium CO2 Diffuser