AquaMaxx Fr-se GFO Carbon and Biopellet Hang-on Filter Media Reactor Chamber Diameter: 3.2" Height: 14.6" Maximum Capacity: 1.0L (1000mL) Using GFO: up to 150 gallons, Using Activate Carbon: up to 75 gallons,Using BioPellets: up to 50 gallons Inlet/Outlet: 1/2" hosebarb