The handrail is a 1 ½" round diameter tubing and the main balusters are a 1" square with 1/8" wall thickness. If your stair has to meet any building codes we will add extra center balusters to achieve a minimum of 4" spacing between balusters. The center column comes with 1/4" x 10" round weld on base plate. Each stair comes in one section or spliced if desired by the customer, which bolts back together with the supplied hardware included. No welding is required. The standard finish on our aluminum stairs is a mill finish. Other finishes are available upon request.