I bought a waterer like this when I got my birds a few months ago. Straight poop, its about the most annoying thing Ive ever worked with. If you dont get the seal EXACTLY right, it leaks. Not right when youre there, but hours later when you come back and the floor is covered with water. The slow air leak allows the water to move out and eventually overflow. If you listen very carefully, sometimes you can hear the air hissing in. Most times not. Ive about had enough. Are the metal ones any better?