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

Block – Free

Left

Arrowheads

Basic Arrows

Core Line

Move Left

Resize Move

Ultimate Bold

Navigation Button Left

Navigate

Core Flat

Core Solid

Left Controller Left

Gaming

Swipe Left

Hand Gestures

Left Circle

Outlined Line - Streamline Material

Roundabout Left

Hardware

Sharp Line - Streamline Material

Chevron Left

UI Actions

Turn Left

Transportation

Ramp Left

Nova Line

Layout Left

Paragraphs Tables

Triangle Arrow Split Left 1

Multiple Triangle Arrow

Sharp Line

Arrows Swipe Left Alt

Single Line Arrow

Move Left 3

Transform Actions

Move Left 2

Navigation Left 3

Navigate Paginate

Move Left 1

Move

Plump Line

Rotate Left 3

Edit

Nova Solid

Layout Left Sidebar

Layouts

Align Left

Text Formatting

Core Remix

Left Click

Mouse

Micro Solid

Left Align 2

Flex Line - Free

Left Chevron

Ultimate Regular

Direction Left

Diagrams

Arrows Left

Cyber Line - Free

Navigation Left

Plump Remix

Cyber Line

Arrow Left

Keyboard

Left Trigger

Ultimate Duotone

Left Distance

Design Tools

Freehand Duotone

Arrow Left 1

Rounded Line - Streamline Material

Left Chevron Circle

Sharp Solid

Sharp Neon

Sharp Line - Free

Align Left 1

Sharp Solid - Free

Ultimate Light

Align Left 2

Align

Core Gradient - Free

<p>Flex is all about the curves. Its smooth curves brings fluidity and dynamism to your designs with a modern appeal.&nbsp;The Duo style is perfect for projects that require differentiation between actions, using color to convey meaning effectively. It also allows you to customize the line thickness.&nbsp;All Flex Duo icons are designed on a 14px grid with a 1px default stroke and two customizable colors.</p>

Flex Duo

**Summary**: Flex's two-color system — 1px organic line with dark periwinkle blue primary and lighter blue secondary, adding colour depth and structured hierarchy with the flowing visual quality unique to the Flex family. Organic curves keep the two-color system from reading as corporate despite the blue palette, making it softer and warmer than equivalent duo systems in more geometric families. The tone signals organic structure: "we differentiate through flow, not rigidity." Best for modern SaaS wanting a two-tone icon system with organic visual quality, products with a brand blue where the duo adds depth without imposing rigid geometry, and feature and documentation sections.

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

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## Fit & Recommendation

### Primary use cases

- Modern SaaS wanting a two-tone icon system with organic visual quality
- Products with a brand blue where the duo treatment adds depth without rigid geometry
- Feature comparison, help, and documentation sections

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## Brand & Cultural Identity

### What it communicates

> "We differentiate through flow, not rigidity."

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## Visual & Technical Specs

### Visual properties

| Property | Value |
|----------|-------|
| Stroke weight | 1px |
| Fill | None (line only) |
| Corner treatment | Smooth fluid curves |
| Color | Dark periwinkle blue + lighter blue secondary |

### Emotional Scores

Flex Duo is somewhat warm — the blue two-color palette is cool, but organic 1px curves soften the coolness compared to geometric duo sets. It is among the softest sub-styles in the catalog — the 1px organic curves in a two-color system remain visually soft despite the structural intent. It is somewhat warm on friendliness — the two-color system adds structure while organic shapes keep it from reading as corporate. It is near neutral on playfulness leaning slightly serious — colour differentiation reads as functional 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 — the two-color system adds semantic structure while organic curves retain a natural quality.

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## Pairing & Compatibility

### Typography pairing

- **Primary**: Plus Jakarta Sans — humanist warmth appropriate for the flowing two-color system
- **Alternative**: Outfit — modern humanist, pairs with the blue duo
- **Body**: Inter Regular
- **Avoid**: IBM Plex Sans — engineering register creates personality conflict with organic curves


<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

Left Controller Left icon - Flex Duo Set

Download Left Controller Left SVG vector or transparent PNG icon in Duo, Filled, Stroke style(s) for Sketch and Figma. It belongs to Flex Duo vectors SVG collection.