This large hopper-type poultry drinker has a very large lid to be easily filled from a bucket or hose. The lid has two simple tabs to hold it down, and also an air breather valve in the peak. There is then a float valve in the bottom of the hopper which maintains a constant water level in the drinker bowl. This water level can be adjusted by wing-nuts underneath. The drinker rim height is only 7cm, so suitable for a wide range of birds. Diameter 44cm, height 50cm overall. Another quality Crown poultry product.