The Squirrel Bustertm is truly squirrel proof! Here’s how it works. Openings in the shroud (bottom section of the feeder) align with seed ports and provide birds access to the seed. When a squirrel climbs onto the feeder, its weight automatically forces the shroud down and closes the seed ports. Squirrels and large birds are foiled but not harmed in any way. Dishwasher safe! High water temperatures and powerful dish detergents clean and sanitize every bit of your feeder. Clean feeders are as important to wild birds as clean dishes are to humans. Wild bird safety is deadly serious business. Spread the word about safe feeders. Adjustable Posi-Grip perch! Squirrel Bustertm Plus perches are adjustable in length and lock into place. Thick perches and textured surfaces provide a secure and comfortable grip for birds. Perches can be shortened to attract small birds such as chickadees and finches while deterring larger birds such as grackles and starlings. Perches can also be extended just en