AquaClear (now Fluval) hang on back aquarium filter for 20 - 50 gallon tanks.
Item is used but in good, fully functional condition. Will require new activated carbon filter stage (easy to find, standard consumable item), and you may wish to replace all stages of the filter material, however the mechanical (sponge) and biological (porous ceramic granules) stages are included.
See my other items for more aquarium equipment, including a brand new example of this filter, heater, tank, air pumps)