The improved design for Millside's Top-Fill Poultry Fountain offers a new cap design that is sturdier and more impact resistant than previous models. This means you don't have to worry when moving a full fountain from one location to another. These plastic poultry and game bird waterers are rust proof, dent proof and easy to fill. Automatically keep water fresh with the vacuum-sealed cap. The opaque jar design reveals the water level so you always know when it's time to fill up.