Edsal UR1848AZ-BLK Steel Storage Rack, 5 Adjustable Shelves with Post Couplers and Plastic End Caps, 4000 lb. Capacity, 72" Height x 48" Width x 18" Depth, Black Frame is made of steel for strength Shelves are made of particle board supported by double-riveted beams and braces and adjust in 1-1/2" increments to accommodate items of varying heights. Item has couplers. Frame has smooth black finish for resistance to corrosion Rivet lock design for assembly without nuts or bolts, instructions included, tools for assembly sold separately