Quantum Storage Systems AD54-2424BK Add-On Kit for 54" High 4-Tier Wire Shelving Unit, Black Finish, 24" Width x 24" Length x 54" Height Kit comes complete with 2 posts and 4 shelves and (8) S-hooks All welded construction with additional wire trussing for high strength characteristics Wire allows air to circulate and light to penetrate for increased product visibility 600 to 800 lbs capacity per shelf, Minimal dirt accumulation Measures 24" wide x 24" long x 54" high