Behind the Design

‍I'm JunYong Youn, a product designer at Spigen Korea. As part of our team, I've witnessed our successful expansion in EDC (Everyday Carry) products over the past three years. In 2024, we're launching Spigen LIFE, a new category that goes beyond EDC to include bags. While I had experience developing molded pouches at Spigen, designing a sling bag was entirely new territory, making this project particularly memorable. Let me share the development journey of the KD410, our first sling bag in the Spigen LIFE collection.

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* What is a Sling Bag?

A sling bag is a compact, single-strap bag that can be easily swung from back to chest, offering quick access to your belongings while wearing it.

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Spigen Sling Bag KD410

The KD410 accommodates everything from daily essentials to compact gaming devices like the Nintendo Switch. We selected premium Cordura fabric for its exceptional durability.

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*What makes Cordura Fabric special 

Cordura combines lightweight construction with superior resistance to abrasion, tears, water, and wind. This versatile fabric offers extensive design possibilities through its range of colors and textures.

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Target Market and Design Philosophy

We designed this sling bag for urban commuters in the Bay Area, primarily targeting office workers and students who rely on public transit and bikes. These users prefer front-accessible bags for convenient, considerate use in crowded spaces. Our design meets the growing need for a compact yet efficient bag that safely stores both electronic devices and daily essentials with easy access.

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Design Approach

Our development process focused on three key areas :

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1. User-Centered Design

Our research focused on understanding daily usage patterns, essential items carried, and user preferences based on insights from our U.S. sales team and market experience. This helped us create a product perfectly suited for our target users: urban professionals and students in the Bay Area's major tech hubs.

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2. Enhanced Functionality 

Based on our research, we incorporated four key design principles: Compact, Easy Access, Practical, and Multi-Functional. Key features include:

• Built-in bottle opener for easy access
• Adjustable Velcro shoulder strap pad
• Detachable keychain in front pocket
• Quick-release buckle for effortless removal
• Versatile storage with inner strap and outer D-ring

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3. Material and Color

We selected Cordura fabric for its premium quality and durability. Moving away from traditional dark tones of Spigen LIFE products, we added bold yellow accents to enhance visibility on e-commerce platforms. We upgraded smaller components with consistent PU materials and added yellow accents to details like the Spigen LIFE logo and bar tack stitching, a reinforced sewing technique that prevents unraveling.

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Development Process

Perfecting the design involved multiple iterations, from initial 2D concepts through three rounds of prototypes. We meticulously refined every aspect—from shape and size to texture and details—in close collaboration with our suppliers.

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Material Selection 

What looks great on screen often differs in reality. Through extensive testing, we moved from Cordura 1680D to 840D, finding the perfect balance of durability and weight. The Denier (D) measurement indicates fiber thickness:

• 40-80D : Light materials (stockings, thin umbrellas)
• 200-400D : Standard bag materials
• 500-1,000D : Heavy-duty bags
• 1,000D+ : Military-grade gear

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Detail Refinement

We meticulously reviewed everything from thickness measurements in millimeters and the internal and external composition to sub-materials like zippers and zipper pullers, as well as the direction the zippers open.

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1. Enhanced Waterproofing : To protect belongings in bad weather, we replaced regular zippers with waterproof ones.
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2. Improved usability : We unified the opening direction of the zippers on the main compartment and the front/back pockets for better accessibility. This design ensures users can open the bag the same way, regardless of its orientation. Especially when worn across the front of the body, having all zippers open in the same direction makes retrieving items smoother and faster—an invaluable feature during busy commutes or while on the move.
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3. Reinforced Durability : We used bar tack stitching at the connection between the shoulder strap and the bottle opener to prevent the fabric from splitting and to enhance durability. 
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4. ‍Improved Strength : We increased the thickness of the shoulder strap from 1.2mm to 1.5mm, a 25% increase. This change enhances the strap’s ability to withstand the pulling and twisting forces generated when using the bottle opener. It also improves weight distribution on the shoulders, providing greater comfort when carrying heavier items.

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Quality Assurance

To ensure exceptional durability and reliability, we conducted comprehensive testing including temperature resistance, drop impact, salt spray exposure, and UV resistance. We also performed extensive durability tests on all components, particularly focusing on high-stress areas like zippers and velcro attachments.

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Market Performance

The KD410 has shown steady growth in U.S. Amazon sales since launch. Its versatile design, accommodating both daily essentials and gaming devices, positions it well for future growth, particularly during new gaming device releases. At Spigen, we remain committed to enhancing your daily life through thoughtful design and innovation. Stay tuned for more exciting products from our team!

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