Starter unit includes two uprights and one set of cross braces. Storage room is increased when the add-on unit is ordered. Add-on unit consists of one upright and one set of cross braces for joining to the starter set. Capacity is 500 pounds per arm. Distance between levels is 10". There are 7 storage levels. Choose either single sided or double sided steel racks. Each upright requires four (4) anchor bolts, sold separately. Painted finish.