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FR
One articulated mechanism. Four dimensions of control.
Forward lean
The fore-aft plane, adjustable
A thumbwheel nut lets you set your forward lean, and it stays put.
Freedom of the ankle
Physiological freedom
In released mode, the mechanical constraint is removed: physiology sets the limit.
Flexion
Mechanical behaviour, measurable
A moment, an angular stiffness, an angle: physical quantities, not an index.
Lateral alignment
The lateral orientation, adjustable
The strap comes to meet the shin where it is, and the ski stays perfectly flat.
The pivot of the exoskeleton does not explain everything. It is the complete architecture, geometry, axes, linkages, elastic elements, interfaces, adjustments, that produces the final behaviour. The pivot is its structuring kinematic principle.
The contrast with the traditional architecture fits in one line: a rigid shell constrains the relationship between the leg and the ski; an articulated system organises and controls it. The difference is measured in degrees of freedom that are actually available and controllable.
A thumbwheel nut moves the stop against which the lever comes to rest. You choose your forward lean, and it stays put.
In engaged mode, the architecture controls the movement of the ankle. In released mode, it no longer imposes a mechanical stop on it: the mechanical constraint is removed, and physiology becomes the only limiting factor.
In a conventional boot, “flex” is a global, non-standardised index that cannot be compared from one brand to another. At zUFO, behaviour is described by physical quantities: a moment around the pivot, an angular stiffness, an angle.
No leg is perfectly vertical. The mechanism shifts the strap sideways to meet the shin where it is, while keeping the lever vertical, so the ski stays perfectly flat.
Adjustable. Measurable. Predictable. Consistent.
Before · after
zUFO changes what can be mechanically controlled in a ski boot.
Four parameters every skier knows by name, and that very few really use, because they are difficult, imprecise, or simply absent. zUFO finally makes them accessible, and gives you the power to master them: hence its name, zUFO⁴, zUFO to the power of four.
| Parameter | Before (rigid shell) | With zUFO⁴ |
|---|---|---|
| Forward lean | Non-existent or limited to two positions | A wide adjustment range, simple and effective |
| Freedom of the ankle | Reserved for ski touring | Limited by the ankle, not by the mechanism |
| Flexion | No standardised index, no comparison possible between models | Measurable behaviour |
| Lateral alignment | Possible but expensive, as it is done in a workshop on some high-end models | Adjustable on the slope, when stopped, without tools |
The starting point
These are not four improvements obtained one by one. They all stem from the same choice: rather than improving the rigid plastic shell, breaking free of it.
In its place, an exoskeleton: a mechanical object whose function is to transmit forces between the leg and the ski. This change of technology opened up a new field of possibilities.
A mechanical object can be adjusted. A shell remains a compromise.
Separating the functions
Today · the rigid-shell ski boot
A single material drives three variables that cannot be optimised together.
Comfort or precision. Warmth or performance. Never both.
With zUFO⁴ technology · the exoskeleton
One architecture, two dedicated elements: each function gets the one that suits it.
Morphology
Our architecture does not start from any average leg: the structure itself leaves room for the differences between bodies.
Calf circumference follows neither height nor shoe size. A small person can have a strong calf, a tall person a slim one. A single shape imposes an average, and those who differ from it feel it: it pinches, or it won't close.
Beyond this ordinary variation, there are the situations where an illness, an accident or a malformation has come into play. We had not anticipated them, and they came to us.
Since the project became public, skiers have been writing to us spontaneously: an ankle that has been operated on and is now locked, a foot that can no longer bear a rigid shell or that they can no longer buckle. Many have given up skiing and hope to return to it. A hospital department of physical medicine and rehabilitation even contacted us. During the trials of winter 2025-26, with a prototype whose boot was integrated into the exoskeleton, a person who can no longer wear conventional ski boots was able to ski.
It was not in our specifications, but we understood that our approach could also matter to some people. zUFO is not medical equipment, and nothing replaces the advice of a health professional. But if we enable those who can no longer wear shell boots to get back to skiing, we are happy and proud of it.
Eco-design
Conventional ski boots are very rarely recycled, because they assemble a very large number of materials, often glued together.
zUFO takes the problem the other way round. Because the architecture separates what a shell mixes together, the transmission of forces, waterproofing, insulation, each function lives in its own part. And each part of the exoskeleton can be designed in a single material, assembled and taken apart without special tools or glue.
What can be taken apart can be repaired: parts are replaced one by one, you change what wears out, not the whole. The parts can thus be sorted, and recycled in their own stream where one exists.
This eco-design approach was carried out with a specialised agency, within the methodological framework of ADEME, the French agency for ecological transition. Real, quantified results will be established on the final product, which will take us from design to measurement.
Six years of research and development, three patents.
Technology protected by patents FR 3 109 278 and US 12,396,514 (HF Consulting) and FR 3 131 509 (K2i), exploited under an exclusive licence by K2i.
A transmission exoskeleton, designed for the ski approach.
This is only the beginning. Our technical foundation, the zUFO⁴ architecture, is designed for several disciplines, and in time for alpine skiing.
It was also designed to take a suspension, which the 2021 patent already provides for, with dampers that can be disengaged between the sole and the uppers: we believe tomorrow's ski boot will have one.
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