Impeccable, air pump well suited to my tank 30 l. Really silent pump. One small regret that prevents me put 5 gold stars (the word "perfect") concerns the booklet as if it does say quon can change the dust filter, it does not indicate dismantling protocol below. Maybe is it a simple little door? I do not know and have no desire to go: I installed the pump immediately replacing that of another brand that has "passed away" after years of loyal service APS and the pump 50, placed on a small marble plaque (anti vibrations!) next to the aquarium and at its base "purrs quietly." that's perfect!
