Squirrel Slammer Tube Bird FeederSquirrel Slammer Tube Bird Feeder Weight sensitive ports close automatically under a squirrel's weight. The metal base and feeders prevent squirrels from causing damage. This bird feeder has 3 separate feeding ports and holds 3. 5 lbs. of seed. A squirrel proof feeder that can hold a variety of bird seed mixes and attracts cardinals, chickadees, nuthatches, and many more backyard birds. Squirrel proof Weight sensitive ports that close under a