Mount the attachment rail (bolts included) to the side of our Mega-Tray storage units to keep small items out of the way but easily attainable. Ten cups with lids fit into the tray to hold a wide variety of small items or store the cups in one of the mega-trays and use the caddie for long items like rulers, shears, markers, etc. Caddie can be wall-mounted using screws (not included) instead of the bolts. A great way to deal with a variety of tools and supplies.