The Hydor Koralia #4 Powerhead is a unique aquarium circulation pump that can be easily attached to the inside of an aquarium with the specially designed magnet holder.Additional photoFlow Rate: 1200 gphConnections: None8.5 WattsWater flow can be directed freely with the special sphere shaped connection to the exclusive combination suction cup and magnet supportThe magnet can safely hold Koralias applied in tanks with glass (or acrylic) up to 15mm thick. The magnet is specially covered to prevent corrosion.