Good but not without fault
This makes drinking out of wide mouth bottles so much easier. Unfortunately, mine has been leaking consistently no matter how much I tighten it. Also, and this may just be a fault of my own, but no matter how much I clean this, I'm having a lot of difficulty getting rid of a bad smell on it. It's great great if it doesn't leak and smell but sadly mine has both those qualities.
Rating: 3 stars