Interface Essential

Business

Images Photography

Money Shopping

Programming

Computer Devices

Phone

Mail

Map Travel

Food Drink

Nature Ecology

Entertainment

Shipping

Culture

Health

Work Education

Artificial Intelligence

Arrows

Streamline 3.0

Ultimate

Core

Flex

Sharp

Plump

Micro

Freehand

Streamline Material

Nova

Cyber

Streamline Vault

Logos

Pixel

Google Material

Tabler

Remix

Feather

Iconoir

Carbon

Solar

Lucide

Brand Logos

Bootstrap

Atlas

Unicons

Ionic Icons

Phosphor

MingCute

Font Awesome

Majesticons

Mynaui

Radix

Heroicons

Flagpack

Sharp Neon - Free

Check

Sharp Duo - Free

Block – Free

Check 2

Basic UI

Sharp Pop - Free

Ultimate Colors - Free

Sharp Solid - Free

Sharp Flat - Free

Ultimate Light - Free

Sharp Line - Free

Outlined Line - Streamline Material

UI Actions

Sharp Line - Streamline Material

Flex Neon

Validation

Cyber Duotone

Status

Sharp Duo

Plump Duo

Ultimate Duotone

Form Validation

Ultimate Light

Sharp Flat

Flex Pop

Ultimate Bold

Flex Remix

Kameleon Duo

Strategy

Plump Pop

Cyber Line

Check 1

Flex Gradient

Plump Remix

Ultimate Colors

Sharp Line

Flex Duo

Ultimate Regular

Rounded Line - Streamline Material

Sharp Pop

Sharp Gradient

Plump Gradient

Sharp Solid

Plump Line

Flex Line

Plump Solid

Flex Flat

Flex Solid

<p>Flex is all about the curves. Its smooth curves brings fluidity and dynamism to your designs with a modern appeal.&nbsp;The Flat style is easy to integrate into projects that need icons with a more illustrative purpose, working best at larger sizes. All Flex Flat icons are designed on a 14px grid with two customizable colors.</p>

**Summary**: Flex's illustrative sub-style — solid flat two-tone blue fills on fluid organic silhouettes, producing a more contemporary and natural-feeling flat illustration register than geometric flat sets. Fluid organic edges soften the flat fill quality, making this register warmer and more natural than Sharp Flat or Core Flat at equivalent blue tonal palette. The tone signals organic illustration: "we illustrate nature's geometry." Best for onboarding and product tour illustrations at display sizes, feature explainer content in modern consumer products, and marketing where organic silhouettes feel more contemporary than geometric flat alternatives.

**Last updated**: 2026-04-23

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## Fit & Recommendation

### Primary use cases

- Onboarding and product tour illustrations at display sizes
- Feature explainer and help content visuals
- Modern consumer product marketing where organic silhouettes feel more contemporary than geometric flats

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## Brand & Cultural Identity

### What it communicates

> "We illustrate nature's geometry."

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## Visual & Technical Specs

### Visual properties

| Property | Value |
|----------|-------|
| Stroke weight | None |
| Fill | Solid flat fills, two-tone |
| Corner treatment | Fluid organic silhouettes |
| Color | Dark blue + light blue tonal |

### Emotional Scores

Flex Flat is somewhat warm — the blue tonal system is cool, but organic silhouettes add warmth that geometric flat sets lack. It is one of the friendlier sub-styles in the catalog — flat fills on organic silhouettes produce flowing shape edges that soften the fill. It is one of the friendlier sub-styles in the catalog — the two-tone blue in organic shapes reads as modern and considered, with mild approachability. It is somewhat warm on playfulness — organic flat illustration reads as contemporary and considered rather than playful or severe. On its human↔mechanical character, it is one of the more human-feeling sub-styles in the catalog — fluid organic silhouettes read as natural forms, not diagrams.

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## Pairing & Compatibility

### Typography pairing

- **Primary**: Outfit — modern humanist, appropriate for the illustrative flat icon context
- **Alternative**: Plus Jakarta Sans — warm humanist, works in illustrative contexts
- **Body**: Inter Regular or DM Sans
- **Avoid**: Cold geometric or monospace fonts


<p>Flex is a fluid icon family inspired by nature’s curves. It favors smooth, flowing forms. More organic than Core and subtler than the chunky Plump. Read about the <a href="https://blog.streamlinehq.com/flex/" rel="noopener noreferrer" target="_blank">design process</a>.</p>

Fluid icons

Check Thick

Check Thick icon - Flex Flat Set

Download Check Thick SVG vector or transparent PNG icon in Flat style(s) for Sketch and Figma. It belongs to Flex Flat vectors SVG collection.