A dual outlet suits 6-8 layers (recycled drum supplied by customer or 4010) 2 x 4009 cups.The 4009 dual trigger chicken drinker with 2 by 4009 cups are useful for chooks with large combs, also as water doesn't remain in the cup it allows less mess and mould to build up, chooks learn this easily, except silky and polish breeds of chooks who struggle with the concept, also with really fluffy heads targeting the trigger is harder.
The water in a drum or container should be no higher than 30 cm above the 4007 water cup, these are low pressure devices. Please Tighten Cups onto elbows using the Polynut not by grabbing lubing cup.