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

Kameleon Pop

Test

Learning

Kameleon Duo

Kameleon Colors

Flex Gradient

Test Folder

Files Folders

Test Tube

Core Remix

Micro Solid

Science

Flex Solid

Core Pop - Free

Core Flat

Ultimate Bold

Test Tubes

Laboratory

Sharp Line

Core Solid

Core Duo

Flex Line

Pregnancy Test

Babies

Core Duo - Free

Plump Remix

Plump Pop - Free

Cyber Duotone

Test Tube 2

Cyber Line

Micro Line

Core Gradient - Free

Core Remix - Free

Core Solid - Free

Core Neon - Free

Core Line

Core Line - Free

Plump Solid - Free

Ultimate Light

Plump Solid

Plump Pop

Plump Duo

Core Flat - Free

School Test Art 1

School

Kameleon Colors - Free

School Science

Ultimate Regular

Test Tube Holder

Ultimate Colors

Laboratory Test Stool Cup

Laboratory Tests

School Test Results

Laboratory Test Blood Finger

Plump Remix - Free

School Test Art

<p>Flex is all about the curves. Its smooth curves brings fluidity and dynamism to your designs with a modern appeal.&nbsp;The Gradient style is best suited for designs where impact and immersion are key, especially on dark backgrounds. All Flex Gradient icons are designed on a 14px grid using filled shapes as gradient colors.</p>

**Summary**: Flex's most expressive sub-style — full-spectrum multi-stop gradient fills on fluid organic silhouettes, creating a distinctive high-production marketing presence that geometric gradient sets cannot replicate. Flowing organic edges amplify the warm gradient stops in a way that flat geometric fills cannot. The tone signals expressive flow: "we are expressive and flowing." Best for high-production landing pages, hero sections, and brand marketing at display sizes where flowing gradient silhouettes create visual distinction from geometric gradient equivalents.

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

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## Fit & Recommendation

### Primary use cases

- High-production landing pages and feature banners
- Hero sections where icons are focal points
- Brand marketing at display sizes where flowing gradient silhouettes create distinction from geometric gradient sets

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## Brand & Cultural Identity

### What it communicates

> "We are expressive and flowing."

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## Visual & Technical Specs

### Visual properties

| Property | Value |
|----------|-------|
| Stroke weight | None |
| Fill | Solid fills with full-spectrum multi-stop gradients |
| Corner treatment | Fluid organic silhouettes |
| Color | Full-spectrum gradients per icon |

### Emotional Scores

Flex Gradient is one of the warmer sub-styles in the catalog — full-spectrum gradients with warm tones on organic silhouettes allow flowing shapes to amplify the warm gradient stops. It is one of the softer sub-styles in the catalog — gradient fills on organic silhouettes with flowing edges prevent the hardness of flat geometric fills. It is one of the friendlier sub-styles in the catalog — rainbow gradients in flowing shapes read as expressive and contemporary. It is one of the more playful sub-styles in the catalog in a refined way — gradient energy with organic forms reads as creative and modern, more refined than outright playful. On its human↔mechanical character, it is one of the most human-feeling sub-styles in the catalog — colour expressiveness combined with organic silhouettes reads as human creative expression.

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## Pairing & Compatibility

### Typography pairing

- **Primary**: Syne — flowing display geometric mirrors the expressive quality of gradient-filled organic silhouettes
- **Alternative**: Plus Jakarta Sans Bold — humanist weight holding alongside the visual richness of gradient fills
- **Body**: Outfit Regular or DM Sans
- **Avoid**: Cold geometric grotesque; cartoon rounded display 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

Test Tube icon - Flex Gradient Set

Download Test Tube SVG vector or transparent PNG icon in Gradient style(s) for Sketch and Figma. It belongs to Flex Gradient vectors SVG collection.