Flux.2 Klein
A lightweight 4B parameter FLUX variant. Fast 4-step generation with low VRAM requirements.
- Developer: Black Forest Labs
- License: Apache 2.0
- HuggingFace: black-forest-labs/FLUX.2-Klein
Variants
| Model | Steps | Size | Notes |
|---|---|---|---|
flux2-klein:q8 | 4 | 4.3 GB | Good quality |
flux2-klein:q6 | 4 | 3.4 GB | Better quality |
flux2-klein:q4 | 4 | 2.6 GB | Smallest FLUX |
flux2-klein:bf16 | 4 | 7.8 GB | Full precision 4B |
Defaults
- Resolution: 1024x1024
- Guidance: 0.0
- Steps: 4
Flux.2 Klein-9B (alpha)
Note: Klein-9B is in alpha. The Qwen3 encoder (hidden_size=4096) differs from Klein-4B (hidden_size=2560) and is not yet fully supported.
A larger 9B parameter FLUX variant. Distilled for fast 4-step generation with higher quality than the 4B Klein.
- Developer: Black Forest Labs
- License: Non-Commercial
- HuggingFace: black-forest-labs/FLUX.2-klein-9B (gated — requires HuggingFace license acceptance)
Variants
| Model | Steps | Size | Notes |
|---|---|---|---|
flux2-klein-9b:q8 | 4 | 10 GB | Good quality |
flux2-klein-9b:q6 | 4 | 7.9 GB | Better quality |
flux2-klein-9b:q4 | 4 | 5.9 GB | Smallest 9B |
flux2-klein-9b:bf16 | 4 | 18 GB | Full precision, gated, 2 shards |
Defaults
- Resolution: 1024x1024
- Guidance: 1.0
- Steps: 4
Note: The 9B model requires ~29GB VRAM for BF16. The BF16 variant is gated on HuggingFace and requires license acceptance before download.
Recommended Dimensions
| Width | Height | Aspect Ratio |
|---|---|---|
| 1024 | 1024 | 1:1 (native) |
| 1024 | 768 | 4:3 |
| 768 | 1024 | 3:4 |
| 1024 | 576 | 16:9 |
| 576 | 1024 | 9:16 |
| 768 | 768 | 1:1 |
Using non-recommended dimensions will trigger a warning. All values must be multiples of 16.
Example
Flux.2 Klein Q8 — 4 steps, seed 100:
mold run flux2-klein:q8 "A minimalist zen garden with raked sand patterns, a single cherry blossom tree, morning mist" --seed 100
Flux.2 Klein BF16 — 4 steps:
mold run flux2-klein:bf16 "a majestic owl perched on a mossy branch in a moonlit forest"
Architecture
Flux.2 Klein uses a Qwen3 text encoder (BF16 or GGUF, layers 9/18/27), a shared modulation transformer (BF16 or GGUF), and a BN-VAE decoder.