It creates excellent and beautiful air, but it is not silent. Some of the internal components resonate or "find" somewhere and make a sound like a rattling that is very annoying. With a slap, it stops, but a few minutes later it starts again. Maybe I got a defective unit, I will open it, if I can, to see if it can be fixed

Very good air pump and powerful because I have connected two tubes with a splitter and there are many bubbles in both. The only disadvantage despite the reputation of eheim that they are silent, which is partly true, is the noise it makes after a few hours of operation. Compared to other air pumps I have bought in the past, there is no comparison.

It looks high-quality and like it will withstand the test of time. It doesn't make much noise (I have it on the lowest power it can offer).

Particularly quiet pump, satisfactory performance, complete with all necessary accessories, it also had two check valves in the (new) packaging that were not mentioned in the description, good price.