The Pop Bottle Waterer with Attachment Spring is a great economical way to supply water to your animals! This universal waterer works on the old-fashioned snap on pop bottles or the screw-on 12 or 16-ounce soda bottles. Simply screw plastic bottle to the waterer and secure the bottle to a cage with included spring. Waterers fit through 1-inch square openings in cage or pen. Please watch our helpful demo.