Takes on the many advantages of the professional 3 series - strong performance, optimal energy efficiency, quiet operation, suction aid, safety hose adapter. The technology has also been improved with the integration of the new "Xtender" button. If performance is reduced due to clogging of the fine filter medium, the button can be set to redirect the flow. Biological filtration is maintained, and the maintenance interval can be extended by a few days. Three sizes are available for aquariums up to 250, 350, and 600 liters. Models 250 and 350 are also available with an integrated heater as a thermofilter (T). The professional 350e can additionally be controlled electronically via a PC.