# Siblings collection
> Feature introduced in Pipeline 6.2
The second required metafield is **`theme.siblings`**
```
theme.siblings
```
The content type is **Single line text** and **One value**.
This metafield maps each product to the correct collection handle for the siblings.
Start by defining a **Products** metafield and name it **Siblings collection**. Then change the Namespace from `custom` to `theme` and the key to simply `siblings`.
{% hint style="info" %}
Important steps (**two** changes):
* Rename **`custom`** to **`theme`**
* Rename the key to **`siblings`**(Be sure to change from siblings\_collection to simply siblings)
{% endhint %}
Two Changes required in the Namespace and key
Next, add a description. You can name this one *Collection handle for siblings*.
Then click on **Select content type** and choose **Single line text** as the type and **One value**:
**Save** the definition.
### Important - Check the saved metafield
Your second metafield should look like this:
{% hint style="success" %}
Please ensure you change the Namespace and key to this custom version for Pipeline:\
\
\&#xNAN;**`theme.siblings`**\
\
By default, the namespace begins with**`custom`**. This will need to be changed to**`theme`** and also **trim** the **key** to just**`siblings`**.
{% endhint %}
The content type is **Single line text** and **One value**.
### Product setup
Next, we will use these newly defined metafields in the Product Setup for each product:
{% content-ref url="siblings-product-setup" %}
[siblings-product-setup](https://pipeline.groupthought.com/siblings/product-siblings/siblings-product-setup)
{% endcontent-ref %}
