Wire mesh construction also allows for easy identification of shelf contents and prevents dirt and other debris from accumulating on the shelves because of the holes in the mesh. Most wire mesh decking has U-shaped channel supports, also known as struts, to support the load. With this waterfall decking, the wire mesh extends across the top and down the front of the beam to provide more support, and is more desirable in the marketplace. Reverse waterfall decking can provide containment of a loose product to prevent the product from falling behind the rack system. Lay-in decking rests inside the step of the beam, and wire mesh does not waterfall over the beam. Some types of decking are manufactured with solid metal instead of wire mesh. Even though the solid decking provides a greater distributed weight capacity, it is discouraged by fire inspectors because sprinkler systems cannot spray through the shelves to levels below.