The Crown Automatic Drinker/Feeder combination is meant for poultry and larger pigeon breeds. If you want to use it for smaller pigeon breeds, just lay a 2 x 4 on each side, flat side down. The end where the float valve is, is the drinker section. It is much smaller than the feeder section because the water section fills itself when the water level goes down.The drinker system is meant for a low gravity water system or may also be used as a gravity system, which just means running a hose from a water bucket or barrel from a higher point than the drinker. The feeder part is filled by lifting the top and adding feed as needed. The medium is 24 in. long x 2 3/4 in. wide x 7 in. high and the large is 30 1/2 in. long x 2 3/4 in. wide x 7 in. high. Includes 60 in. hose to connect to your pvc pipe. Combination Crown Feeder with Automatic Drinker 24 in.