The Yankee Whipper features collapsible, mechanical perch rods that are weight-activated using a patented design. The curved perches attract a wide variety of birds including cardinals, but squirrels will cause the perches to collapse. The perches reset automatically after the squirrel slips off. Its UV-stabilized polycarbonate seed tube can hold up to 5 pounds of seed, while its metal cap fits so snugly that squirrels cannot pry it off. The tube is long enough so that squirrels cannot hang down from the top and reach the seed. The interior is properly baffled to direct seed to the 4 seed ports positioned around the tube. Metal parts have a beautiful evening blue finish. 21" long, 4 3/4" diameter.