Add on this six-compartment unit to your Storex literature sorter (sold separately) to instantly increase your storage capacity. Heavy-duty plastic construction will not sag or bow and outlasts cardboard alternatives for long-lasting use for years to come. Integrated label holder on each compartment allows you to customize each space to prevent misfiling. Space-saving design is stackable up to 12 units high to provide up to 72 different compartments. Each compartment measures 9-1/2" x 12" and holds up to 5 lb.