Sturdy Mail Sorter is made of 5/8" thick furniture-grade particleboard with adjustable hardboard dividers that form up to 18 compartments. Each compartment holds up to 5 lb. Large sorting slots accommodate oversized envelopes. Durable laminate finish will complement any setting. Black plastic molding provides an eye-catching accent to the finish while providing a place for the included labels. Stack up to two high to increase sorting capability. Solid fiberboard back provides stability.