This is 4 tier wire shelf,all the shelf is can adjust height. This Heavy Duty 4-Shelf Metal Shelving Unit in Black Steel Finish is made of steel wire shelving.The weight limit for each shelf is 250 pounds, and the total weight limit for the entire shelf is 1000 pounds. The storage shelves provide an enormous amount of space for you and no occupy too much space.You can use this wire shelving in the kitchen bedroom garage and more. Tools, books,household appliances and other things can be placed on this wire shelving.