Boltless multipurpose shelving features a unique design with time-saving, snap-together assembly. Only a rubber mallet is required to secure supports of this six-shelf Capstone Shelving Adder Unit. Double-wall post construction conceals the keyhole slots for a clean, attractive appearance. Four of the six 42" wide steel shelves are adjustable in 1-1/2" increments to create custom openings for box storage, archives, supplies and more. Steel shoulder rivets combined with double-wall steel uprights and shelf supports offer up to 650 lb. shelf capacity.