Customer Services

Customer Services

Dual Fit System

Two fit behaviours in one boot — comfort on the approach, precision when it gets technical.

DFS (Dual Fit System) is AKU’s fit and lacing innovation designed to give you the right feel for the right moment: Comfort Walking for long approaches and mileage, and Precise Climbing when terrain becomes steep, rocky, exposed or technical. In plain English: you can keep the forefoot comfortable for distance, then quickly increase forefoot wrap for more control and sensitivity.

  • Comfort Walking: secure instep hold while keeping maximum forefoot volume.
  • Precise Climbing: fast-lock cord wraps the forefoot and reduces toe volume for precision.
  • Built for mixed terrain: used on AKU’s most technical approach, via ferrata and mountaineering models.
What this means for you

More all-day comfort on the walk-in, with the option for higher precision and control when foot placement matters.
AKU fit system for comfort + technical precision.
What is DFS (Dual Fit System)?
 

DFS is a technical two-mode lacing system. In Comfort Walking, a traditional lace path locks the instep while leaving maximum space at the forefoot. In Precise Climbing, a fast-lock cord tightens through dedicated anchor points and webbing to wrap the forefoot, reducing volume at the toe for increased precision.
DFS in motion
 
Switching from Comfort Walking to Precise Climbing for more control when terrain turns technical.
How to use it (when to switch modes)
 
Comfort Walking mode

Your default setting for distance. Aim for a secure instep and heel, with comfortable toe room. This is ideal for approaches, longer mileage, and when feet naturally swell over time.

Use this when

You’re walking distance, carrying load, or prioritising all-day comfort.
Precise Climbing mode

Tighten the fast-lock cord in small steps until the forefoot is wrapped and stable. The goal is more sensitivity and control on rock, not maximum tightness.

  • More precision: improved edging and accuracy on small holds/features.
  • Less movement: reduced forefoot slop on steep, rocky terrain.
  • More confidence: better control in exposed passages and careful descents.
Use this when

Scrambling, via ferrata, technical rock, steep mixed ground, or precision-focused descents.
Jargon buster (plain English)
 
Forefoot volume
How much space you have around the front of your foot and toes.
Edging
Using the edge of the sole on small rock features — benefits from a more precise fit.
Toe bang
When toes hit the front on descents. Often improved by securing heel/instep first, then tuning forefoot tension.
Find DFS models
 

DFS appears on technical Outdoor models (approach, via ferrata, mountaineering and some fast hiking). Browse by category below.

Outdoor
Hunting
Tactical
Professional

Tip: if you tell us your activity (approach/via ferrata/scrambling) and sock thickness, we can help you choose the best size and how to tension each mode.
Care & spares FAQ's
 

DFS relies on smooth lace travel and intact lace hardware. Most real-world issues come from grit, worn laces/cord, or accidental damage to the fast-lock components.

1
Rinse grit from lace paths
After dusty or muddy days, rinse eyelets/anchors and the fast-lock cord path so tension stays even.
2
Replace worn laces/cord early
If laces/cord look fuzzy, flattened or frayed, replace them — worn laces can slip and reduce control.
3
Broken “plastic part” / hardware
If any DFS fast-lock hardware or lace anchor is damaged, stop using that mode and arrange a repair assessment. In the UK, use Lancashire Sports Repairs (AKU UK official partner) with clear photos of the damaged component.
Fit safety note

For descents, prioritise a secure heel/instep first (to reduce slide), then fine-tune the forefoot with DFS. Don’t over-tighten — control should feel firm, not painful.
DFS FAQs
 
Is DFS the same as Dynamic Fit?
No. DFS is AKU’s Dual Fit System (two lacing modes). Dynamic Fit is a separate technology that adapts heel tension with your stride (covered on its own technology page).
Do I have to re-lace the whole boot to switch modes?
Usually no. Most users keep Comfort Walking set for the day, then tension the fast-lock cord for Precise Climbing when needed. Tighten in small steps until the forefoot is stable.
I feel pressure or numbness in Precise Climbing — am I doing it wrong?
Probably over-tension. Precise Climbing should feel wrapped and controlled, not painful. Loosen slightly and re-tighten gradually. If pressure persists, the model/fit may be too low-volume for your forefoot.
Does DFS change sizing?
DFS changes how the fit can be tuned (hold/volume), not the boot length. Choose size based on correct length and heel security, then use DFS to adapt comfort vs precision.
My toes hit the front on descents — will DFS fix it?
Sometimes. First secure the heel/instep (Comfort Walking) to reduce slide, then fine-tune forefoot wrap. If toe bang continues, you likely need more length, different socks, or a different last/fit.
Can I get replacement laces / DFS cord?
Yes. If you need a lace/cord replacement, use AKU UK lace/spares options where available. If you’re unsure which lace set you need, tell us your model name and size and we’ll confirm the correct replacement.
The DFS “plastic part” / hardware looks damaged — what should I do?
Stop using that mode to avoid worsening the damage and arrange a repair assessment. In the UK, contact Lancashire Sports Repairs (AKU UK official partner) with photos so they can advise what’s possible for your model.