EHEIM Professionel 4+ External Canister Filter. The EHEIM professionel 4+. EHEIM's best external filter but now with an integrated emergency button. They have adopted the many advantages of the professional 3 series powerful performance, optimal energy efficiency, quiet operation, priming aid, safety hose adapter but have also improved the technology by incorporating the new button. In the event the output is reduced due to the fine filter media blocking, the button can be adjusted to redirect the flow. The biological filtration is maintained and the service interval can be extended by a few days. Advantages of the EHEIM professionel 4+ filter: Premium class external filters with all the advantages of the professionel 3 series Additional control function (Xtender) to counteract blocked filter media and extend intervals between cleaning Square canister for high stability and large filter volume High flow capacity with low energy consumption Adjustable pump output. High performance ceramic axle guarantees quiet running and durability Integrated self priming aid to initially prime the filter Safety hose adapter can only be removed when the valves are closed Top prefilter effectively traps large dirt particles and allows for longer service intervals. Simple to remove and easy to clean. Individually filter baskets with Easy Clean grid Fully equipped with original EHEIM filter media and installation accessories. Available in the following sizes: EHEIM Professionel 4+ 250 * For aquariums of about. 120 l * For aquariums up to approx. 250 l * Pump power (50 Hz) per hour of approx. 950 l * Pumping head approx. (H max at 50 Hz) 1.50 m EHEIM Professionel 4+ 350 * For aquariums of about. 180 l * For aquariums up to approx. 350 l * Pump power (50 Hz) per hour of approx. 1,050 l * Pumping head approx. (H max at 50 Hz) 1.80 m EHEIM Professionel 4+ 600 * For aquariums of about. 240 l * For aquariums up to approx. 600 l * Pump power (50 Hz) per hour of approx. 1,250 l * Pumping head approx. (H max at 50 Hz) 1.80 m