This Shelving Insert for the General Purpose Folding Mail Cart is designed to hold three-sided flat trays. Our handy insert can also be used under Carrier Cases. This shelving insert features tube steel construction. This item MUST SHIP VIA COMMON CARRIER USPS. Activities order this item from the Topeka Material Distribution Center. Refer to Publication 247, Material Management Equipment and Supply Catalog for Item Numbers and Ordering Instructions. This product is not intended for the NOA Program. However, a special discount is applied.