Mix and match tubs to create your own color-coded book cart! Each tier holds one set of tubs: six 6" wide Lifetime Book Tubs or three 12½" wide Lifetime Divided Tubs or Lifetime Open Tubs. 1"-thick-steel cart with 10-year warranty has a blue powder-coat finish and heavy-duty, industrial casters (two locking). Minor assembly required. Overall size: 40" high x 43" wide x 18" deep. Standard Create-a-Cart Frame also available . Please note tubs are sold seperately.