Handling Unit information. Identifies and decribes the material used to build a shipping unit or container. The ID identifies the material of the container or the shipment package The Description describes the material or container a product or item is shipped in. This is most often used for cases where a product is shipped in a returnable container. Examples include: Steel Case Rail Road Car Special Hazardous Material Casea Stackable and Returnable have been added to the schema TierCount- maximum number of units per tier if stacked MaxTiers= maximum number of tiers high