520 lbs. (52 Seats) All-aluminum bleacher seat planks and steel under structure provide a lightweight, stable bleacher. Seat planks are 10" wide non-skid aluminum. Planks are supported by a strong, galvanized steel understructure made of 3/16" x 1-1/2" steel angle. Planks and understructure can be powder coated to match your team colors!. Four row bleachers do not exceed 30" in height. Check local codes for guardrail requirements. Ships Freight.