30"Deep Chrome Wire Shelving Unit with Four Shelves There are numerous advantages to getting a deeper chrome wire shelf as opposed to traditional particle board storage. The Chrome Wire Four Shelf Unit has ventilated shelves that let light in and allow air to flow through. These units are easy to maintain, fully adjustable, and incredibly durable, supporting over 500 pounds per shelf (when evenly distributed). If you wish to improve on your wire rack shelving, consider purchasing an add-on unit or upgrading to the 5 shelf storage system.