Tennsco Welded Bookcase - 34.5" x 13.5" x 78" - Steel - 6 x Shelf(ves) - Black Tennsco Metal Bookcases. Straight lines permit flush alignment side-by-side and back-to-back. Commercial grade. Commercial-grade steel construction provides years or reliable storage. Shelves adjust in 2'' increments. Powder-coated finish. Four-shelf unit has three extra-deep 13 1/2'' adjustable shelves that raise and lower.