Interface Essential

Technology

Computers devices electronics

Coding apps websites

Internet Network Servers

Business Products

Work office companies

Money Payments Finance

Shopping Ecommerce

Shipping Delivery

Content

Design

Images Photography

Music Audio

Video Movies TV

Files Folders

Users

Avatars

Emails

Phones mobile devices

Messages Chat

Social medias rewards rating

Travel

Hotels spas

Wayfinding

Food Drinks

Furnitures Decoration

Lamps Lights Fire

Clothes Footwear Accessories

Tools Construction

Ecology

Nature Farming

Pets Animals

Weather

Health Beauty

School Learning

Science

Culture Religion

Romance

Family Babies Kids

Holidays

Sports

Outdoors Recreation

Entertainment Event Hobbies

Video Games

Crime War Protection

Transportation

Maps Navigation

Building Construction

Landmarks

Real Estate

Arrows Diagrams

Logos

Streamline 3.0

Ultimate

Core

Flex

Sharp

Plump

Micro

Freehand

Streamline Material

Nova

Cyber

Streamline Vault

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

Mailbox 2

Mailbox

Mailbox 4

Mailbox 1

Mailbox 3

Markunread Mailbox

Mailbox Full

Mailbox Post

Mailbox House

Us Mailbox

Mailbox Full 1

Mailbox In

Markunread Mailbox Fill

Email Mailbox Close

Mailbox Post 1

<p>Ultimate is the world’s largest icon family, designed by 8 expert designers. The Duotone style enhances visual depth by combining colored lines and filled shapes, perfect for matching brand or project colors. Key advantages: 1—Customizable colors. Apply up to four different colors to icon elements. 2— Adjustable stroke thickness. Create looks ranging from thin to bold for varied aesthetics.</p>

Ultimate Duotone

**Summary**: 1px stroke with a three-layer fill system (colored stroke + colored tint fill + selective white fill), rounded throughout, color-customizable — the most expressive and depth-forward Ultimate sub-style for UI work. The layered fill system produces a gentle visual depth that feels modern and considered rather than flat or heavy. The tone signals personality and brand expressiveness: color hierarchy built into the icon itself rather than into the surrounding layout. Best for marketing pages, onboarding flows, and feature sections where icons carry brand color and visual dimension beyond standard UI chrome.

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

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## Fit & Recommendation

### Primary use cases

- Marketing pages and feature differentiation sections
- Onboarding flows and empty states
- Landing page sections where icons carry more visual weight than UI chrome
- Products with a defined brand color where icons should reflect it
- Hero visuals that need depth without full illustration

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## Brand & Cultural Identity

### What it communicates

> "We have personality and depth."

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## Visual & Technical Specs

### Visual properties

| Property | Value |
|----------|-------|
| Stroke weight | 1px |
| Fill | Three-layer: colored stroke + colored tint fill + white fill applied selectively |
| Corner treatment | Rounded |
| Color | Teal/cyan default (customizable to brand color) |

### Emotional Scores

Ultimate Duotone is one of the friendlier sub-styles in the catalog — the default teal/cyan is a cool colour, but the partial fill softens the coldness noticeably, landing as somewhat warm overall. It is one of the softer sub-styles in the catalog — the 1px stroke combined with a low-opacity fill creates a gentle, layered softness. It is one of the friendlier sub-styles in the catalog — the colour and fill combination reads as inviting rather than formal, leaning clearly friendly. It is one of the more playful sub-styles in the catalog — the two-tone colour adds personality and levity; not fully playful but clearly expressive. On its human↔mechanical character, it is one of the more human-feeling sub-styles in the catalog — colour warmth combined with fill depth humanises the icons visually.

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## Pairing & Compatibility

### Typography pairing

- **Primary**: Plus Jakarta Sans — rounded, slightly personality-forward, matches the tonal depth
- **Alternative**: Poppins — geometric warmth, compatible with color-forward icons
- **Body**: Inter or Mulish in Regular weight
- **Avoid**: Monospace fonts (personality mismatch); serif display at high contrast


<p>The world's largest icon family with encyclopedic coverage. Designed over twelve years, Ultimate offers every concept from common to rare icons. It's a neutral style and fits most use cases.&nbsp;</p>

The encyclopedia of icons

Mailbox Post icon - Ultimate Duotone Set

Download Mailbox Post SVG vector or transparent PNG icon in Duo, Stroke, Filled style(s) for Sketch and Figma. It belongs to Ultimate Duotone vectors SVG collection.