Cups require a source of water at a pressure of less than 5 lbs. P.S.I. which is provided by a pressure reducing valve or by gravity tanksplaced less than 5’ above the drinkers. Each cup can handle up to 40 birds. The cup system is the most sanitary watering system available. Cups have a spring-loaded trigger stem for positive shut-off of water. Water flows only when the bird’s beak is in the cup. There are no messy wet spots as with nipple drinkers.