These bottles are great!
12 oz. Chew Proof Water Bottle - Feeders & Waterers - Small Pet - PetSmart
1) Made of glass
2) The spout can be removed from the cap for thorough cleaning
3) Never leaks if you make sure the spout is tightly in place (easy to adjust).
4) I feel glass stays cleaner than plastic, because it's non-porous.
5) Cute little duckies inside so you can quickly see the water level.
6) Some reviews on Petsmart said the caps rusted, but I've had mine for 5 months with no problems.
7) It has a flat side, so it sits snug against the cage.
As you can tell I'm a huge fan! haha