With the new professionel 4+ series, Eheim once again sets high standards in aquarium filter technology. Many of the details and useful functions have been taken over from the previous filter model, the professionel 3. The most striking feature of the new professionel 4+ external filter is the emergency button Xtender. This button makes it possible to have a little more time until the next cleaning of the external filter is carried out. Who of us aquarists isnt familiar with this problem? Always when we have the least time the water throughput is low and the filter is blocked calling for an immediate cleaning. Using the emergency button Xtender you will gain a few more days without any adverse effect on the biological filtration capacity. The gradually adjustable Xtender button makes the water pass partly around the microfilter inside the filter system so that the water throughput is restored and the aquarium filter goes on working as usual. The new Eheim professionel 4+ and its insta