These bin systems utilize a slotted tray with removable disks to partition the individual bins. The 16 wide unit comes with four trays and maximum of 24 compartments, while the 24 wide unit has 5 trays and a maximum of 72 compartments. Disks are easily removed to allow you unlimited flexibility in the layout of compartment sizes. The unit come unassembled for easy shipping and goes together in a snap, since most of the connections are slip together. Both units are slotted to accept the optional sign holder.