> For the complete documentation index, see [llms.txt](https://docs.zephyrintel.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.zephyrintel.com/asset-detail/bill-of-materials-bom-and-stock-tab/understand-the-bom-tree-and-part-statuses.md).

# Understand the BOM tree and part statuses

The BOM table lists an asset's parts as a tree. Assemblies can contain parts, and those parts can contain their own sub-parts. Every row is expanded by default so you see the full structure at once.

> **Screenshot placeholder:** the BOM table for an asset with nested assemblies, showing an **Obsolete** badge with a successor, an **Inactive** row and a **Recommended Spare** badge, plus the count summary line above.

### Columns

| Column      | What it shows                                                                   |
| ----------- | ------------------------------------------------------------------------------- |
| Part Number | The part's number, with expand and collapse arrows for rows that have children. |
| Description | The part's description.                                                         |
| Qty         | Quantity. Shows 1 when the quantity is 1 or less.                               |
| Item #      | The item number, when one is recorded.                                          |
| Type        | Blank for a plain part; shows the type for assemblies and kits.                 |
| Status      | A badge, described below.                                                       |

### Status badges

| Badge                               | Meaning                                                                                            |
| ----------------------------------- | -------------------------------------------------------------------------------------------------- |
| No badge                            | The part is active and current.                                                                    |
| **Obsolete**                        | The part is no longer the latest model. Its part number is struck through.                         |
| **Obsolete** with "→ {part number}" | The part is obsolete and has a replacement. The replacement part number appears next to the badge. |
| **Inactive**                        | The part is marked inactive. The whole row is dimmed.                                              |
| **Recommended Spare**               | The part is flagged as a spare worth stocking.                                                     |

If a part qualifies for more than one badge, Signal shows Inactive first, then Obsolete, then Recommended Spare.

### Count summary

Above the table, a summary line totals the list, for example "48 parts · 3 assemblies · 5 recommended spares · 2 obsolete". Signal leaves out any segment that is zero, so a BOM with no obsolete parts will not mention obsolete at all.