The Squirrel Buster Standard raises the standard in everything a wild bird feeder should be. Here's why: Award-winning Squirrel Buster technology is truly squirrel-proof. Over 1 million very happy customers have confirmed it. Patented weight adjustable closing mechanism shuts out squirrels as well as some heavier undesirable birds. Seed Saver Technology eliminates seed losses to pilfering squirrels. These savings alone pay for the feeder. Seed Tube Ventilation keeps seed fresh. Both perching and clinging footholds increase bird activity. Chew-proof components stop annoying squirrel damage. Detachable Component System for easy cleaning, filling and servicing. Dishwasher safe for total sanitizing. Stainless steel perches and hanger. UV stabilized components