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 the water back into the aquarium, insert the external heater in between, insert the plug and set the water temperature you want The integration in the filter circuit ensures a very even distribution of the water temperature with an accuracy of +/- 0.5 °C and a switching interval of 1.0 °C in the aquarium LED display of current and desired temperature. Interchangeable, screw-on (3/4'') hose connections for 12/16, 16/22 and 19/25 mm incl. hose securing. Total length 30.5 cm Package contents: 1 in-line heater 300 W for aquariums from 90-300 l (80-120 cm) with hose connections for 12/16, 16/22 and 19/25 mm and cleaning brush