> For the complete documentation index, see [llms.txt](https://docs.imerit.net/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.imerit.net/labeling/labeling-tools/relation/single-relation.md).
# Single Relation
The Single Relation labeling tool allows you to create a relation between two annotations.
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The Single Relation tool is supported across the Audio, Image, Video, DICOM, PDF, and Text labeling editors.
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Single relations are not visible unless the user is hovering over them with the mouse cursor.
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## How to add a Single Relation tool to your project
From the project’s *Settings* tab, enter the *Label Set* section.
Click on *Add Category*. From the list that appears, click on *Single Relation*.
A new row will appear named *Single Relation*. Click on it to expand it.
Give your single relation tool a title and description.
Enable the *Required* toggle if you want to force labelers to create a single relation for each asset. When the toggle is disabled, labelers will be able to save and move to the next asset without creating the single relation.
### How to Draw a Single Relation
Click on the label where you’d like the single relation to start. Click on the second label where you’d like the relation to end. Press N on your keyboard to finalize the relation.
After having created the relation, you can change its direction by clicking on the small arrow inside the relation's box.
#### Single Relation Directions
* **Forward:** the first label points at the second label.
* **Backward:** the second label points at the second label.
* **Bidirectional:** The labels point at each other.