Inserting inside ofenclosuresand supplying a smooth, solid surface that keeps items in place, these plastic wire shelf liners are a practical and protective accessory for your 18"d x 48"w wire shelving setup. Durable, 1/8" thick PVC construction Rounded corners position around posts Holds up to 300 lbs, evenly distributed Moisture and chemical resistant Liners are cut-to-order and arefinal sale. Please measure shelf prior to purchasing.