They are much nicer than XP2,3 etc, Cascade Canister Filters, and the Fluval FX5. You must supply the pump yourself so you get to decide what kind of flow you require. I have a mag drive 14 powering mine and I have the model 340 or 350. First canister is filled with very porous sponge material and the second canister is filled with polybead. It has a better flow rate and much higher bio capacity than my FX5. In my opinion they make XP3's and all those caliber filters look like a joke. I will soon be purchasing a big eheim canister so we will see how it compares to that.