Welded Seam Technology

Stealth Welded Seam Technology provides seams stronger than if sewn. Won't delaminate. Adhesive-free: no glues of any kind. Airtight. Waterproof.

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What’s the Story Behind Stealth?

Stealth Welded Seam Technology

Stealth have developed and patented a novel method of welding seams that uses ultrasonic edge-joining combined with HF radio welding of a tape seal. No glues, no adhesives, no delaminating. Fabrics as light as 10D can be welded, yielding watertight and airtight seams twice as strong as any sewn seam.

Seams are stronger than the material itself. The Stealth logo can be incorporated into your design, showing off your product as different, with special characteristics, complementing your design image and building the brand.

Stealth is being produced in our own  purpose-built factory, Weltop Outdoor Co Ltd, who are already set up with the machinery and the skillset required to make these uniquely-strong and long-lasting airtight and watertight seams for your outerwear, tents, sleeping bags, packs and sacks.


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What Makes Stealth So Important?

Unique Technology

The combination of Ultrasonic and RF joining techniques enables you to design waterproof and airtight seams that also happen to be stronger than if sewn.

Already in Production

Shell Jackets in 2.5L and 3 L
Down Jackets
Synthetic insulated Jackets
Sleeping bags
Bags and Packs


Your designers will love the clean lines possible with Stealth Welding and your customers will certainly appreciate the style, strength, and performance of your products.


No glue or adhesives
Light and clean looking
NO puckering like sewn seams.


Stealth welded seams provide unparalleled strength and flexibility with no risk of delamination. Seams are twice as strong as sewn seams

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What Makes Stealth Unique?

Visual Appeal

Strong Welded Seams give your outerwear and equipment the look you want. A clean outlook with no puckering.

Strong Welded Seams

Our welded seam is twice as strong as a sewn seam and will not leak or delaminate. There are no adhesives or glues to give way over time.

Any Design

Stronger airtight seams with clean lines that never  leak can give you the freedom you need to design a market-beating product.


Our Seam Welding method is patented. US Patent 10751948B has been granted and other patents are pending. We combine two tried and tested sealing technologies in a new, revolutionary, way.

100D or Lighter Fabrics!

Stealth Seam Welding is capable of joining  fabrics from 100D to as light as 10D. We are already producing rucksacks, jackets, tents and sleeping bags.

Airtight Seams

Down Jackets and Sleeping Bags will retain warmth and will keep down where it belongs: inside. There are no needle-holes to leak down, and less down is needed than for a normal sewn product.


No other seam technology can perform as well as Stealth. Whether you are buying lightweight outwear or heavy-duty sailing packs, your seams will outperform.

Brand Buyers

Your Brands will benefit from this new, strong, waterproof and airtight seam technology. Let your designers loose.

So Much More

We’ve been working on Stealth for three years. The production machinery has been built. We are producing jackets, tents, bags, accessories and sleeping bags.