"This pump would get 5/5 paws except for a few things of note. The pump runs on an electromagnetic diaphragm, which pumps air into the tubes. Basically, when the power is on, a simple lever connected to a regular magnet and a diaphragm is moved by an electromagnet near the regular magnet. In theory this is a basic and reliable design, but not entirely. If the pump meets any resistance it will force the lever out of its socket, forcing you, the owner, to open the pump and push it back in, unless you LOVE loud pumps that barely pump air. So yeah, I like this pump when it works, I ended up supergluing the lever which is held in place with foam, into its socket so it would not CONSTANTLY pop out and wake the neighbors. What is unfortunate is that these tend to be some of the best pumps out there for a budget consumer like me. I'd recommend opening it up when you get it, and put a drop of superglue on the fulcrum of the lever."