Solid Shelf Add-On Kit allows you to expand your Starter kit by sharing a set of posts. Configuration options include straight line, back to back and right angles (L-Shape). Each add-on unit consists of 4 shelves, 2 posts and 8 shelf clamps. Additional shelves may be purchased separately. Includes 2- 74" Posts, 4- 24" x 60" Solid Galvanized Steel Shelves and 8 Shelf Clamps