Features Includes Automatic Water Feeders + Black T's and Springs + adjustment tool. 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, uses 5mm allen key to adjust Specifications Tubing ID: 5/16" Weight: a .5 ounces per assembled nipple "T" Color: White Be sure to install the "Flared Out" part of the nipple on the bottom side