Aluminum seat planks and galvanized steel under structure provide the most durable, stable bleacher on the market. Seat planks are 10" wide non-skid aluminum. Galvanized steel understructure is made of 3/16" x 1 1/2" steel angle. Shipped freight. Made in the USA. 21' long. seats 42. aluminum & galvanized bleachers. 425 lbs.