Extra Shelf, Color Black, Load Capacity 150 lb, Number of Shelves 1, Overall Depth 18 in, Overall Width 36 in, Product Type Shelf, Adjustable No, Compatible Manufacturer Model Number BC18-30, BC18-30M, BC18-42, BC18-42M, BC18-52, BC18-52M, BC18-72, BC18-72M, BC18-84, Compatible Product Type Bookcases, Overall Height 3/4 in