The Hydor Koralia #1 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: 400 gphConnections: None3.5 WattsWater flow can be directed freely with the special sphereshaped connection to the exclusive combination suction cup and magnetsupportThe magnet can safely hold Koralias applied in tanks with glass (oracrylic) up to 15mm thick. The magnet is speciallycovered to prevent corrosion.