Features Includes 20 Automatic Water Feeders + 20 Black T's and 20 Springs Ideal for Rabbits, Ferrets, Chinchilla and other small Mammals. Manufacturer recommends 3 animals per nipple Does not require a drip cup. Can be used with a variety of wire cages Very easy and quick to assemble Built-In Cage Clip On The Side Built-In Adjustable valve Specifications Tubing ID: 5/16" 360 degree stainless steel nipple "T" Color: Black Be sure to install the "Flared Out" part of the nipple on the bottom side