> For the complete documentation index, see [llms.txt](https://help.sbtinstruments.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://help.sbtinstruments.com/item-register/individual-items/external-filter.md).

# External filter

Place between your BactoBox® and the tubing kit

{% columns %}
{% column %}

<figure><img src="https://4199970748-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FAjOYV4v43T0TFlSRqgAp%2Fuploads%2Fgit-blob-89dcc709f23b336798aa8089ad83c0d87f71339d%2Fexternal-filter--photo.png?alt=media" alt=""><figcaption><p>External filter</p></figcaption></figure>

<a href="mailto:sales@sbtinstruments.com" class="button primary" data-icon="envelope">Contact SBT to purchase</a>
{% endcolumn %}

{% column %}
:label: Sales item `PF01`

:package: Pack holds **2 filters**

:globe\_with\_meridians: Country of origin **China**

:label: HS code `9033.00.90`

:straight\_ruler: Pore size **40 µm**
{% endcolumn %}
{% endcolumns %}

## Included in

<table><thead><tr><th width="100">Item no.</th><th width="300">Item</th><th>Details</th></tr></thead><tbody><tr><td><code>FC03</code></td><td><a href="/item-register/consumables/flow-cell.md">Flow cell incl. two external filters</a></td><td><mark style="color:$info;">Every flow cell ships with one pack, so two filters, one to fit and one spare.</mark></td></tr></tbody></table>

{% hint style="warning" %}
**Do not substitute a third-party filter**

The pore size and the fitting both matter. A different filter changes what reaches the flow cell.
{% endhint %}

## Install and replace

Always have an external filter between your [BactoBox®](/item-register/bactobox-r/bactobox-r.md) and the [tubing kit](/item-register/bactobox-r/bactobox-r/in-the-box/tubing-kit.md).

See [Install tubing kit](/getting-started/installation/install-tubing-kit.md) for instructions on how to replace the external filter.

{% hint style="success" %}

### Replace the external filter when you replace the flow cell <a href="#replace-the-external-filter" id="replace-the-external-filter"></a>

One filter goes in, and the second one in the pack is your spare.

**Run a** [QC test](/getting-started/qc-test.md) **when you replace the external filter.**
{% endhint %}

## Gallery

<figure><img src="https://4199970748-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FAjOYV4v43T0TFlSRqgAp%2Fuploads%2Fgit-blob-cc0db9ebb3e7a098c840b2eafaafb290b2e41154%2Fphoto--external-filter-packaging.png?alt=media" alt="" width="270"><figcaption><p>Pack of 2 external filters</p></figcaption></figure>


---

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