After using the water from the nest, the water from the pot will automatically drain until the birds finish filling the whole thing, because the smaller outlet, so the water can not be polluted. It greatly reduces the busy work of the owner and often solves the problem of changing the water. You can add water for a few days without changing the water. Plastic hooks to attach to the cage. Suitable for small bird/parrot, aviary, budgie, cockatiel, peony, etc. Strong Plastic Molded Color: Green and White Capacity: 60mL(S); 140mL(L) Size: S (applicable to cage below 30*23*39)/L (applicable to cage above 35*28*47CM) Quantity: 1Pc Note: Size for manual measurement, may be 0 to 2cm error, belongs to normal phenomenon. Due to the difference between different monitors, the picture may not reflect the actual color of the item. Thank you! Package Included(No Retail Package): 1Pcx Pet Bird Food Feeder