Squirrel Buster Plus Bird Feeder: Guaranteed Squirrel Proof and Large Bird Proof Effective against Red and Gray squirrels and Grackles, Starlings, Doves, etc. Weight-sensitive perches protect seed from squirrels and large birds. The patented Squirrel Buster Plus™ wild birdfeeder is both squirrel proof and large bird proof. Thousands of delighted bird lovers (including my bird and squirrel loving Boston Terrier Maggie) have confirmed it. Openings in the birdfeeder shroud (bottom section of the feeder) align with seed ports to give birds access to the birdseed. When a squirrel climbs onto the feeder, the weight of the squirrel automatically forces the shroud down to close the seed ports. Squirrels and large birds lose access to birdseed but are not harmed in any way. Built-to-Last Construction: Made of rugged UV-filtered ABS and Polycarbonate resins and powder-coated aluminum components. Hangers, springs and fasteners are made from stainless steel. Dishwasher Safe Design: Easily cleans to maintain a safe and healthy feeder. Clean feeders are as important to wild birds as clean dishes are to humans. Grimy bird feeders can be a source of illness that can be fatal for birds. With squirrel Buster Plus TM detachable components it is effortless to provide the birds you love with a safe and healthy feeder. Regular cleaning of your bird feeder is essential and should never be delayed. Spread the word about clean, safe feeders. Detachable Component System™: Components are designed to be assembled and dismantled easily by hand, without tools. Seed Tube Ventilation System™: Most transparent bird feeder seed tubes trap solar energy just like a greenhouse. The air in Squirrel Buster Plus™ rises and escapes through patented water-proof vents at the top of the feeder. The escaping, heated air is replaced by fresh air entering through the seed ports at the bottom of the tube. The birdseed remains fresh, attracting more birds.   Adjustable Posi-Grip Perch™: Thick, adjustable-length perches with textured surfaces provide a secure and comfortable grip for birds. Attract small birds such as Chickadees and Finches (while deterring larger birds like Grackles and Starlings) by shortening the perches. Cardinal Ring System™: The Squirrel Buster Plus™ can be used with or without the Cardinal Ring System™ (included with feeder purchase), an optional posi-grip ring designed especially for Cardinals. The Squirrel Buster Plus™ Cardinal Ring System™ allows Cardinals to eat facing the seed from a secure and comfortable perch. Squirrel BusterPlus Squirrel Proof Bird Feeder Specifications: Birdwatch America Winner for best new product award. Guaranteed Squirrel Proof: Effective against red and gray squirrels and grackles, starlings and doves. Easy to Clean: Dismantles. Dishwasher safe. Bird Food Capacity:  3 quarts /3.5 lbs. (2.8 L / 1.5 Kg.) Seed Options: cracked corn, mixed seed, peanut bits, safflower seed, sunflower kernels and sunflower seed. Removable perches make this wild bird feeder suitable for clinging and perching birds. Weight-sensitive perches protect seed from squirrels and large birds. Dimensions: 22" high x 6.5" diameter.6 seed ports. UV-stabilized polycarbonate constructed feeder withstands the hot summer sun. Construction: UV-filtered ABS and Polycarbonate; powder-coated aluminum components; stainless steel hangers, springs and fasteners Ventilation system circulates air to prevent seed from molding. Easy to Fill: Twist and lift off cap. Hold upside down and shake to get rid of grain "dust." Use a scoop to fill while unit sits in bird seed storage container or balance on the ground. Twist on cap. Rehang. Note: Safe Home Products tested this bird feeder in an Iowa backyard for over 4 months. Birds attracted included Blue Jays, cardinals, etc. Squirrels failed to get seed except what fell on the ground under the tree. Made in China. Limited Manufacturer's Warranty.