# Inventory

In ION, an **inventory item** is a persistent digital twin representing a specific quantity of a part—typically a single serial-numbered unit or a lot-tracked batch.

* **Creation and Persistence:**  
  The inventory item record is created at the earliest opportunity (e.g., the moment a purchase line is entered) and persists throughout the lifecycle of the corresponding physical piece.
* **Rich Metadata:**  
  Each item carries detailed metadata, including:
  * Location
  * Supplier information
  * Cost
  * Lot or serial numbers
  * Quantity
  * Organizational defined attributes
* **Lifecycle Statuses:**  
  Rather than being deleted when consumed, each inventory item transitions through clearly defined statuses:

* On Order
  * Available
  * Work In Progress (WIP)
  * Kitted
  * Installed
  * Scrapped
  * Unavailable

This ensures that you can always determine the current location and state of an item, answering questions such as "Where is serial XYZ right now?" and facilitating accurate audits of each hand-off.
  
  The **Unavailable** status is also used by the issue disposition workflow. When inventory is associated with an issue, a disposition type configured as **Release on Resolve** or **Permanently Unavailable** can move that inventory to **Unavailable** while the issue is being processed or as part of the final disposition. For more detail, see [Disposition Types](/quality/disposition-types.md).
* **Traceability and Searchability:**  
  Multiple inventory items can exist simultaneously for the same part number across various locations or tracking schemes, providing granular traceability without sacrificing ease of search across the factory.