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5.  Flux.2 Klein 4B

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# Flux.2 Klein 4B — FLUX on Your iPhone, iPad, and Mac

Flux.2 Klein 4B is the recommended starting point: a four-step FLUX.2 model that runs on every supported device, from an 8 GB iPhone to any Apple Silicon Mac. It supports negative prompts and on-device prompt rewriting, and shares its text encoder with Z-Image-Turbo, so installing both costs less than their combined size.

[Join the Beta](/en#beta)

![A river winds through a forested mountain valley at sunset, with purple wildflowers in the foreground.](/_astro/flux-klein-4b.1iRlWBLl_Z1FiUUT.jpg)

Generated with Flux.2 Klein 4B in Private Diffusion.

## What Flux.2 Klein 4B Supports

<table class="w-full min-w-[480px] text-left text-sm"><tbody><tr class="border-b border-border last:border-0"><th scope="row" class="w-64 px-4 py-3 align-top font-medium text-ink">iPhone</th><td class="px-4 py-3 text-ink-secondary">8 GB</td></tr><tr class="border-b border-border last:border-0"><th scope="row" class="w-64 px-4 py-3 align-top font-medium text-ink">iPad</th><td class="px-4 py-3 text-ink-secondary">8 GB</td></tr><tr class="border-b border-border last:border-0"><th scope="row" class="w-64 px-4 py-3 align-top font-medium text-ink">Mac</th><td class="px-4 py-3 text-ink-secondary">Any Apple Silicon Mac</td></tr><tr class="border-b border-border last:border-0"><th scope="row" class="w-64 px-4 py-3 align-top font-medium text-ink">Download size</th><td class="px-4 py-3 text-ink-secondary">4.96 GB (2.53 GB when the shared text encoder is already installed)</td></tr><tr class="border-b border-border last:border-0"><th scope="row" class="w-64 px-4 py-3 align-top font-medium text-ink">Steps</th><td class="px-4 py-3 text-ink-secondary">4 (fixed)</td></tr><tr class="border-b border-border last:border-0"><th scope="row" class="w-64 px-4 py-3 align-top font-medium text-ink">Negative prompt</th><td class="px-4 py-3 text-ink-secondary">Yes</td></tr><tr class="border-b border-border last:border-0"><th scope="row" class="w-64 px-4 py-3 align-top font-medium text-ink">Rewrite Prompt (on-device enhancer)</th><td class="px-4 py-3 text-ink-secondary">Yes</td></tr><tr class="border-b border-border last:border-0"><th scope="row" class="w-64 px-4 py-3 align-top font-medium text-ink">Output sizes</th><td class="px-4 py-3 text-ink-secondary">S · M · L everywhere; XL on 16 GB devices</td></tr><tr class="border-b border-border last:border-0"><th scope="row" class="w-64 px-4 py-3 align-top font-medium text-ink">Latent upscaler</th><td class="px-4 py-3 text-ink-secondary">Off · 1.5x · 2x</td></tr><tr class="border-b border-border last:border-0"><th scope="row" class="w-64 px-4 py-3 align-top font-medium text-ink">License</th><td class="px-4 py-3 text-ink-secondary">Apache License 2.0. Your images are yours, including for commercial use.</td></tr></tbody></table>

[← Anima](/models/anima)[Mage Flow Turbo →](/models/mage-flow-turbo)