In-line heater integrated into the hose of the external aquarium filter, removing the need for a heater INSIDE an Aquarium. Easy installation: cut through the hose from the external filter that feeds theWater back into the aquarium, insert the external heater in between, insert the plug and set theWater temperature youWant. The integration in the filter circuit ensures a very even distribution of theWater temperatureWith an accuracy of +/- 0.5 °C and a switching interval of 1.0 °C in the aquarium. LED display of the current and desired temperature. Interchangeable hose connections for 12/16, 16/22, and 19/25 mmWith hoseLocks. TotalLength: 30.5cm. Package contents: 1 in-line heater 300W for aquariums from 90-300L (80-120cm)With hose connections for 12/16, 16/22 and 19/25 mm and cleaning brush.