Serialization is a technique suppliers use to identify products at various pack levels. The process involves ascribing a unique identifier to each parcel at the level required by the individual, company or organization receiving it. (For instance, a wholesaler, hospital or patient). Products rarely ship solely with pack-level serialization. Aggregation is the process of adding higher-level codes outside packs and pallets that identify end user-level products inside. In some cases, there may be multiple aggregations, depending on the stage of distribution. Aggregation makes it easy for supply chain firms to learn more about the contents of a consignment without having to individually account for each pack.