This truly squirrel-proof feeder features 4 ports in a polycarbonate tube that is covered by a metal wire cage. The length of the feeder makes it impossible for squirrels to get to the seed without causing the spring loaded cage to slide down and cover the food ports. The spring is adjustable so you can set it so bigger birds make it close if you wish. It is super easy to take apart for cleaning and holds 1.5 qts of seed.