> ## Documentation Index
> Fetch the complete documentation index at: https://help.polygon-one.com/llms.txt
> Use this file to discover all available pages before exploring further.
# Sizes
> Keeping one packaging unit in several sizes — primary size, dimensions, GTIN, mass per size
## What a size is
The same packaging often comes in several **sizes** — the same folding carton as a 250 g, 500 g and 1 kg variant. Those variants differ only in **dimensions** and **GTIN**; components, role, obligations and the Declaration of Conformity are shared. That is exactly what the hint on the **Sizes** card says while the unit still has only one size:
> If only the dimensions or the GTIN differ, add another size — components and conformity stay shared.
So you create **one** packaging unit with several sizes instead of copying the unit.
**A size and the "Packaging form" are two different fields.** The **Packaging form** in the **Master data** section is the shape — "e.g. folding carton, stand-up pouch, blister – the form, not the size". Dimensions and GTIN do not belong there; they belong to the size.
## The "Sizes" card
On a packaging unit's detail page, in the **Overview** tab below the **Packaging data** card, sits the **Sizes** card. It lists every size with **Reference**, **Name**, **GTIN** and **Dimensions (W × H × D mm)**; the first size also carries the **Primary** marker.
The card is shown for **every** unit, including one with a single size — because the unit's GTIN and dimensions live here.
### The primary size
Every packaging unit has exactly one **primary size**. It is the unit itself: its **GTIN** and its **dimensions** are the unit's, and its reference follows the unit's **internal reference**. That is why the primary size's reference cannot be changed in the dialog; the hint on the field says where it does change:
> The primary size's reference follows the unit's internal reference. Rename the unit, or promote another size first.
The primary size cannot be deleted either — promote another size first via **Set as primary size**.
### Adding, editing and deleting sizes
**Add size** in the card header opens the dialog with **Reference** (required), **GTIN** ("8, 12, 13 or 14 digits"), **Name** and **Width / Height / Depth (mm)**. **Save** creates the size and closes the dialog.
**Save and add another** saves the size and keeps the dialog open: reference, GTIN and name are cleared, the **dimensions stay** — handy when several sizes share the same shape.
**Edit size**, **Set as primary size** and **Delete size** sit in each row's row menu; clicking the row also opens the edit dialog. Before deleting, the dialog asks: "Delete the size '…'? The unit and every other size stay as they are."
**A size that something still points at is not deleted.** The dialog stays open and names what still refers to it — per-size masses, article links and market volumes, each with a count. Re-point or remove those first.
A reference is unique **company-wide**: it may be taken neither by another size nor by another packaging unit, otherwise the dialog reports "This reference is already used by another size or packaging unit."
On a **pool copy** from a [re-use system](/en/ppwr/mehrweg), the sizes belong to the operator: the card cannot be edited and states the reason — "These details are set by the re-use system … and cannot be changed here." The unit's **internal reference** stays yours — and so, with it, the primary size's reference.
A packaging unit can carry at most **50** sizes, the primary one included. Once that limit is reached, **Add size** is disabled and the card states the reason: "A packaging unit can carry at most 50 sizes."
## Creating a new unit with several sizes right away
In the **New packaging** dialog you enter the first size directly in the **First size (primary)** section; further sizes go below it — expand **More sizes (optional)** and add one row per size via **Another size**.
The same **More sizes (optional)** section is in the dialogs that create a unit from a **component selection** and — in the **Shared units** variant — from an **article selection**. Those do not ask for the unit's own GTIN and dimensions; you add them afterwards in the **Sizes** card.
If a size is refused while the unit is being created (for instance because its reference is already taken), **no** unit is created: the dialog stays open with everything you typed and marks the row that has to change.
When **editing** an existing unit these sections are gone — there, every size lives in the **Sizes** card.
## What can differ per size
### Mass per size
A component has a **default weight** — "Default weight of this component. Can be overridden per size below." If the same component weighs more in a larger variant, enter the differing value in the component form under **Mass per size**, with one field per size. An empty field means "no value of its own": the **component's default weight** then applies — as the hint above those fields says: "Leave blank to use the default weight."
In the unit's **bill of materials** the **Mass (g)** column therefore shows the **effective** mass — one value when every size agrees, otherwise a range (such as `0.4–0.7 g`), and "Default …" as long as no size has a value of its own. The column is display only; the link opens the component form, where the values are maintained.
### Articles per size
If a unit carries more than one size, you additionally pick the **Size** — or **Whole unit** — when [linking an article](/en/ppwr/stammdaten/artikel-stueckliste#linking-articles-to-packaging-units). The **Articles** tab then carries an extra **Size** column.
## Sizes in the packaging units list
In the **Packaging units** list, a unit with more than one size carries a button with the count (for example **3 sizes**). Clicking it shows that unit's sizes with **Reference**, **Name**, **GTIN** and **Dimensions** — without opening the detail page. Units with a single size do not show the button.
The unit itself: fields, bill of materials, deletion and retention.
Several sizes in one sheet: one row per size, sharing the reference.