ultralytics/docs/en/reference/nn/modules/block.md

---
description: Explore Ultralytics YOLO neural network modules, Proto to BottleneckCSP. Detailed explanation of each module with easy-to-follow code examples.
keywords: YOLO, Ultralytics, neural network, nn.modules.block, Proto, HGBlock, SPPF, C2, C3, RepC3, C3Ghost, Bottleneck, BottleneckCSP
---

# Reference for `ultralytics/nn/modules/block.py`

!!! Note

    This file is available at [https://github.com/ultralytics/ultralytics/blob/main/ultralytics/nn/modules/block.py](https://github.com/ultralytics/ultralytics/blob/main/ultralytics/nn/modules/block.py). If you spot a problem please help fix it by [contributing](/help/contributing.md) a [Pull Request](https://github.com/ultralytics/ultralytics/edit/main/ultralytics/nn/modules/block.py) 🛠️. Thank you 🙏!

<br><br>

## ::: ultralytics.nn.modules.block.DFL

<br><br>

## ::: ultralytics.nn.modules.block.Proto

<br><br>

## ::: ultralytics.nn.modules.block.HGStem

<br><br>

## ::: ultralytics.nn.modules.block.HGBlock

<br><br>

## ::: ultralytics.nn.modules.block.SPP

<br><br>

## ::: ultralytics.nn.modules.block.SPPF

<br><br>

## ::: ultralytics.nn.modules.block.C1

<br><br>

## ::: ultralytics.nn.modules.block.C2

<br><br>

## ::: ultralytics.nn.modules.block.C2f

<br><br>

## ::: ultralytics.nn.modules.block.C3

<br><br>

## ::: ultralytics.nn.modules.block.C3x

<br><br>

## ::: ultralytics.nn.modules.block.RepC3

<br><br>

## ::: ultralytics.nn.modules.block.C3TR

<br><br>

## ::: ultralytics.nn.modules.block.C3Ghost

<br><br>

## ::: ultralytics.nn.modules.block.GhostBottleneck

<br><br>

## ::: ultralytics.nn.modules.block.Bottleneck

<br><br>

## ::: ultralytics.nn.modules.block.BottleneckCSP

<br><br>

## ::: ultralytics.nn.modules.block.ResNetBlock

<br><br>

## ::: ultralytics.nn.modules.block.ResNetLayer

<br><br>

## ::: ultralytics.nn.modules.block.MaxSigmoidAttnBlock

<br><br>

## ::: ultralytics.nn.modules.block.C2fAttn

<br><br>

## ::: ultralytics.nn.modules.block.ImagePoolingAttn

<br><br>

## ::: ultralytics.nn.modules.block.ContrastiveHead

<br><br>

## ::: ultralytics.nn.modules.block.BNContrastiveHead

<br><br>

## ::: ultralytics.nn.modules.block.RepBottleneck

<br><br>

## ::: ultralytics.nn.modules.block.RepCSP

<br><br>

## ::: ultralytics.nn.modules.block.RepNCSPELAN4

<br><br>

## ::: ultralytics.nn.modules.block.ADown

<br><br>

## ::: ultralytics.nn.modules.block.SPPELAN

<br><br>

## ::: ultralytics.nn.modules.block.Silence

<br><br>

## ::: ultralytics.nn.modules.block.CBLinear

<br><br>

## ::: ultralytics.nn.modules.block.CBFuse

<br><br>