An ingenious innovation: the water is sucked in, filtered, heated at the same time and returned to the aquarium again with the ideal temperature. EHEIM has once again succeeded as a pioneer in implementing this revolutionary idea in a perfect technical way. Only we offer external filters with integrated heating (IHS). There are currently 5 thermofilters of the EHEIM professionel generation (eXperience, professionel 3 and professionel 3e) for aquariums from 120 to 1200 liters. So you have all the advantages of this high-quality filter series and accessory the comfortable Thermo-Funktion (Thermo-Function).