I bought four of the k14s and they are on my overflows. Where their flow patterns collide, it creates mini tornados! My fish don't really swim anymore, they just kind of float in the current! Theyve outdone themselves! Also, the motor is seperate from the base that touches the overflow, which reduces the vibration so they are silent. Simple design and inexpensive. Kudos to them for such a fantastic product! When Gabe gets them y'all better snatch them up quick!