> For the complete documentation index, see [llms.txt](https://emotiv.gitbook.io/extender-manual/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://emotiv.gitbook.io/extender-manual/modes-of-operation.md).

# Modes of operation

Extender has four modes of operation that you can choose from to best suit your needs:

1. **Power-only mode** extends the battery life of your headset
2. **SD card recording mode** allows you to record data to the Extender, rather than to a computer or mobile device
3. **Pass-through mode** directly records data to your computer, bypassing the wireless feature
4. **USB drive mode** allows you to access the data on the SD card when connected via USB.