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

# FreeU - ComfyUI Built-in Node Documentation

> Complete documentation for the FreeU node in ComfyUI. Learn its inputs, outputs, parameters and usage.

> This documentation was AI-generated. If you find any errors or have suggestions for improvement, please feel free to contribute! [Edit on GitHub](https://github.com/Comfy-Org/embedded-docs/blob/main/comfyui_embedded_docs/docs/FreeU/en.md)

The FreeU node applies frequency-domain modifications to a model's output blocks to enhance image generation quality. It works by scaling different channel groups and applying Fourier filtering to specific feature maps, allowing for fine-tuned control over the model's behavior during the generation process.

## Inputs

| Parameter | Data Type | Required | Range      | Description                                                                    |
| --------- | --------- | -------- | ---------- | ------------------------------------------------------------------------------ |
| `model`   | MODEL     | Yes      | -          | The model to apply FreeU modifications to                                      |
| `b1`      | FLOAT     | Yes      | 0.0 - 10.0 | Backbone scaling factor for model\_channels × 4 features (default: 1.1)        |
| `b2`      | FLOAT     | Yes      | 0.0 - 10.0 | Backbone scaling factor for model\_channels × 2 features (default: 1.2)        |
| `s1`      | FLOAT     | Yes      | 0.0 - 10.0 | Skip connection scaling factor for model\_channels × 4 features (default: 0.9) |
| `s2`      | FLOAT     | Yes      | 0.0 - 10.0 | Skip connection scaling factor for model\_channels × 2 features (default: 0.2) |

## Outputs

| Output Name | Data Type | Description                                   |
| ----------- | --------- | --------------------------------------------- |
| `model`     | MODEL     | The modified model with FreeU patches applied |