Fluval U2 Underwater Filter with three stage filtration is ideal for use in fresh, marine or reptile environments, Stage 1 foam removes large particles, In Stage 2, the poly/carbon cartridge traps fine debris, improves water clarity and removes impurities, In Stage 3, BIOMAX provides optimal biological filtration efficiency, Fluval U2 Underwater Filter Features and Benefits:, - Flip Top for quick and easy maintenance, - An adjustable 3 way flow for output flexibility, - Comes complete with 3 way Flow control with Adjustable Output, 2 Foam Pads, 2 Poly/carbon Catridges,40 gram BIOMAX, - Works for freshwater, marine or reptile environments, 3, 8"" length x 5, 2"" width x 8, 7"" height SKU: RCHG0553