Oase’s BioStyle 20 Hang-On-Back Filter is a compact power filter with large filter capacity. Ideal for 20 Gallon Aquariums, Power Consumption, filter 4.5w , 6ft power cable, Max flow rate 100gph, Multi-Stage Filter Cartridges and Biological Filter Foams, Adjustable Flow Control, Energy-Efficient & Quiet Operation, Easy Maintenance indicator shows when replacement cartridge is needed, Adjustable Leveler secures the filter to the aquarium rim, Telescopic Intake 6in – 14in.