New Zealand technical outerwear company Inselberg has teamed up with the country's top mountaineers to create what it believes is the world’s most durable shell jacket.
Frustrated by mountaineering gear that would fail gradually over time, Inselberg set out to develop a shell that could endure season after season of harsh alpine conditions.
To achieve this, Inselberg partnered with members of the Aoraki Mount Cook Alpine Rescue Team (AMCART).
Over 36 months, alpine guide and former AMCART member Jamie Marr tested multiple iterations of the jacket in New Zealand’s Southern Alps, providing critical feedback that shaped both the design and materials.
The result is the Axiom Shell, a four-layer hardshell engineered for the most extreme environments on Earth.
Inselberg founder Jarlath Anderson said the team made 18 prototypes of the shell as it looked for the winning formula, finally landing on a version which features a unique four-layer laminate that delivers twice the waterproof protection of standard alpine shells while maintaining breathability through ventilation zips.
“Three-layer systems are great, until they aren’t. When sideways rain and gusting wind hit you on an exposed ridgeline and you’ve still got hours to go, your shell has to hold. That’s why we chose a four-layer construction, it’s overbuilt by design,” said Anderson.
For final testing, Marr took a late-stage Axiom Shell prototype to Baihe, a rugged granite gorge north of Beijing, known for its steep, sharp terrain and severe temperature shifts.
“Baihe granite is brutal. It’s the kind of surface that destroys outerwear quickly,” said Marr.
“I tested the jacket over multiple days while climbing sharp cracks, hauling gear over rugged surfaces, and scrambling through rough granite gullies. There were no failures, no breakdown and no tearing.”
The trial wasn’t a standard lab assessment but a real-world test designed to push the jacket to its limits in the kind of conditions it was built for.
“The Axiom outperformed any gear I’ve ever worn, and it’s now a permanent part of my kit.”
Anderson launched Inselberg in 2021 to create functional gear to solve real alpine problems. Each product starts with a use case, then goes through prototyping, refinement, and field validation until it’s ready, with the Axiom Shell a direct result of that process.
The Axiom Shell will be available for order on the 30th of July.
