Powder coated zinc die castings. Perches will only hold the weight of smaller songbirds or cardinals. Anything larger will cause the perch to collapse. 5 dia. x 18 long lexan tube prevents squirrels from hanging off roof and reaching seed port openings. Corrosion resistant hardware. Lifetime warranty against squirrel damage. Holds 6 quarts.. Dimensions are 2.5 X 2.5 X 4.5 UPC Code = 739305105638