Safco Heavy-duty desk shelf measuring 8" x 42" x 12" has dividers to keep books and binders upright. Extra-wide deep shelf features nonskid feet to protect desktop and has 3/4" x 1 1/2" retainer lip in the rear for storage.heavy-duty plastic. 8"H x 42"W x 12"D. 3/4" x 1 1/2" retainer lip in the rear. Nonskid feet protect desktop. 100 lbs. capacity. Limited lifetime warranty. Heavy-duty desk riser. Constructed of melamine top in black with cast-aluminum leg. Extra-wide, 12"-deep shelf allows for binders, telephone, monitor, printer, or other desk accessories to be stored. Shelf dividers keep books and binders upright and orderly. Includes a retainer lip in the rear. Removable back rail. Safco Heavy-duty desk shelf measuring 8" x 42" x 12" is made of black heavy-duty plastic for durability.