The Dymax SF 240 Hang On Back (HOB) Filter is a sleek and compact filter that is perfect for aquariums up to 20 gallons in size. Its modern appearance makes it a great addition to any aquarium set-up. The HOB design allows for easy installation and maintenance, making it a user-friendly option for both beginner and experienced aquarists. With a flow rate of up to 240 gallons per hour, the Dymax SF 240 filter provides efficient filtration and keeps your aquarium water clean and clear. Its adjustable flow control also allows you to customize the water flow to suit your specific aquarium needs.