Versus the one piece "S" shaped airlock:Pros: This 3 piece lets in less oxygen, according to a study that Better Bottle put out (google it). Makes sense, since the plastic is thicker and less is exposed to the air. Cleaning is also easier since you can disassemble it. Lastly, this one seems to keep clear longer that the one piece. Cons: If the temperature drops, you'll get sanitizer or water in your beer. The one piece "S" airlock doesn't do that. Overall I like this one better.