> ## Documentation Index
> Fetch the complete documentation index at: https://docs.polymorfa.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Claims and devices

> Claim and release a Sandbox testing session for a signed-in desktop device.

A claim reserves one testing session for your signed-in Inspector device. Open
and release claims from Inspector; you do not need to handle claim identifiers
or connection credentials.

## Open a testing session

1. Install and authorize [Polymorfa Inspector](/desktop-app/install).
2. Sign in and select the organization that owns the Sandbox project.
3. Find the project and testing number on the Inspector home screen.
4. Choose **Open**.

Inspector claims the number for this device and opens its session. If the
session is already open on this device, **Open** returns you to the existing
session.

## Release a testing session

Choose **Release** beside a claimed number. Inspector closes the local session,
releases the claim, and refreshes the available numbers.

Release the number before opening it on another device. Signing out also closes
your active Inspector sessions and releases their claims.

## Troubleshooting

* Choose **Refresh** when a newly created testing number does not appear.
* Confirm that the selected organization still owns the project.
* Choose **Release** on the original device before moving a session.
* If **Open** or **Release** fails, retry once, then follow [Inspector
  troubleshooting](/desktop-app/troubleshooting).

<Columns cols={2}>
  <Card title="Number pool" icon="phone" href="/sandbox/number-pool">
    List and manage testing numbers.
  </Card>

  <Card title="Install Inspector" icon="download" href="/desktop-app/install">
    Download and authorize the desktop testing app.
  </Card>
</Columns>