# Categories

Use this option to group devices by their type on voice assistants (Alexa, Google Assistant) side. It allows you to control the entire group of devices by giving single commands.

**Examples:**

1. voice command "Alexa, lights on" turns on all the bulbs in the room – you don't have to repeat the command for each of them;
2. voice command "Alexa, play the music" starts playing the music from the nearest or all the speakers (depending on assistants presets).

Choose the corresponding device type(s) from the dropdown menu.


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# Agent Instructions: Querying This Documentation

If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question.

Perform an HTTP GET request on the current page URL with the `ask` query parameter:

```
GET https://docs.blynk.io/en/blynk.console/templates/info/categories.md?ask=<question>
```

The question should be specific, self-contained, and written in natural language.
The response will contain a direct answer to the question and relevant excerpts and sources from the documentation.

Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.