This connector is installed at the bottom of a plastic container. It has a 1/4 inch outlet to which a rubber hose can be connected. All of this is used to provide water by gravity to chickens, rabbits, birds, etc. By raising the container higher or lower, you can modify the pressure and flow of water reaching the nipples (PV100P, VARIFLO, etc.) or other types of drinkers (687, 687N, etc.). Note: 14 inches of container elevation from nipples or drinkers results in 1/2 pound of pressure