I went looking for a replacement pump piece for my Python changer because it leaked terribly. All I found was the Aqueon, so went ahead and picked one up. I was very impressed with a much better designed unit. Unlike the Python, which I see now is a design nightmare, this is one piece, so no where to leak. I also love the on/off handle over the bell thing that you have to lift and twist to close. I used to see anything but the Python as a cheap imitation. Glad I tried the Aqueon out. Never looking back.