Penn-Plax Hang on Power Filter. 
Filtration System:
Mechanical- Polyfiber Floss Cartridge, traps floating particulate matter.
Chemical- Activated Carbon Cartridge, removes harmful chemicals, toxins, odors, discoloration and other contaminants.  Internal shelf system spaces carbon throughout cartridge. Prevents teabagging.
Biological- Internal Sponge,optimizes colonization of benefical aerobic bacteria. Removes ammonia and nitrites. 

Other features include: 80Gallons/hour, up to a 10 gallon tank.           Adjustable flow control, Motor-quiet, efficient and maintenance free, Extendable lift tube for maximum depth of tank, Leveling device-keeps filter positioned and stable in most aquariums, Easy disposable replacement cartridge-free cartridge included. Replacement cartridges sold in single and triple packs for your convenience. Also available in four other sizes.