Flat Bac Water Bottles have been specially designed to be the best quality and most unique water bottle of it's kind. The smooth flat surface fits tightly against pet cages and can easily attach inside glass or plastic enclosures. Each bottle comes with complete with an exclusive snap-lock bracket to make refilling fast and easy. Includes the original Floating Duck refill reminder. 8 oz. size is ideal for hamster, gerbils, and pet mice.