These gravity water dispensers are a great addition to any cage! The bottle fits between the cage wires on the out side of the cage ( see photos ) and features a translucent blue so you can easily check the water level . These water dispensers help keep your birds water cleaner longer , are easy to clean , and are great to be used if you plan on traveling or leaving your bird for a few days . available in 5 different sizes, price varies by size. Recommended for small to medium birds like: canaries , finches , parakeets, Conures, and cockatiels . Do not use for large parrots.