Put an end to products falling through the gaps of your21"d wire shelvingwith these blue poly wire shelf liners. Providing a solid, stable base that ensures everything stays in place, this accessory promotes an orderly storage space. Select the right size by matching the liner dimensions to the depth and width of your wire shelves. .025" thick polypropylene construction Moisture and chemical resistant Liners are cut-to-order and arefinal sale. Please measure shelves and see Product Details section below for exact sizing. To accommodate accessories used on wire shelves, liners must be custom cut. Please note in order special instructions box at checkout if needed.