Ultra Cell 4.1

From359,95 
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A.C.M. FRAME
• Anatomically correct design
• Carbon fiber epoxy matrix
• Rigid & lightweight, impact distributing structure

ASYMMETRI-GLIDE HINGE
• Tracks the natural “rolling-gliding” motion of the knee joint
• Asymmetrical design allows each hinge to set properly
• Allows for automatic tibia alignment of lower frame
• Adjustable ext. regulator from 0º to 30º
• Condyle shims for fine tuning fit

A.R.C. CUFF
• Adjustable Retention Control
• Multiform rigid lateral support
• Built in Anti-Rotation connection

ANTI-ROTATION TETHER  (patented)
• Links the brace to the boot, making them as one
• Transfers forces of a lower leg rotation
• Adjustable to suit each individual

TELE-TRI PATELLA CUP (patented)
• Three piece design
• Easily removable
• High impact Nylon 6 material
• Full range of motion coverage of the knee cap

WATER RESISTANT
• Non-corrosive metals
• Non-corrosive composites
• Hand washable soft materials

3.0 Liners (optional)
• Our liners are a low profile material which keeps the straps placed exactly where you want them, offering comfort and strap control.

UNDER SLEEVES COTTON (included with braces)
• Cotton compression sleeves

Undersleeves and Tethers are included.

Because this item is hand built at Asterisk, there may be an additional 2 to 3 day build process before your item will be shipped.

Introducing the hybrid classic! Revised with the success of the 4.0, we have introduced the 4.1. This includes all the features of the 4.0 but eliminating the liners. These liners are still available as an option.

With gear getting smaller and tighter in the knee joint area, the collapsing 3-piece patented patella makes tighter pants easy to maneuver. This brace is also easily repairable in the field with the part available here in our factory in USA. All our braces come with the patented Anti-Rotation Tethers.

The Asterisk Ultra Cell 4.1 — hybrid-classic motocross knee brace with A.C.M. frame, Asymmetri-Glide hinge, and Anti-Rotation Tether. Removable liners, field-repairable. Available at Art of Racing EU.

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Normally ships within 2-3 days with DHL DHL
Worldwide shipping, free over €150 in EU
30-day returns policy
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The Asterisk Ultra Cell 4.1 is the hybrid-classic knee brace from Asterisk — refined and upgraded from the successful Ultra Cell 4.0, now offering everything the 4.0 provided with the added option to remove the liners for a sleeker, slimmer fit. Designed for serious athletes who want professional-level knee protection across motocross, supercross, off-road, snowboarding, and extreme sports.

The Ultra Cell 4.1 uses A.C.M. (Anatomically Correct Matrix) Frame Technology — a carbon fibre urethane matrix frame that delivers lightweight, rigid support while distributing impact forces evenly across the structure. The Asymmetri-Glide Hinge provides automatic tibia alignment and tracks the natural motion of the knee, with an adjustable extension regulator from 0° to 30°. The patented Anti-Rotation Tether links the brace to the boot to prevent harmful lower leg rotation — the primary cause of ACL and MCL injuries in motocross crashes.

The 3-piece Tele-Tri Patella Cup made from high-impact Nylon 6 provides full kneecap coverage even during high-impact motion, while remaining low-profile enough to fit under tight-fitting motocross gear. The Ultra Cell 4.1 is built from non-corrosive materials, is water resistant, and is repairable in the field — components can be replaced without returning the brace.

Key Features:

  • A.C.M. Frame Technology — carbon fibre urethane matrix
  • Asymmetri-Glide Hinge — automatic tibia alignment, 0° to 30° adjustable extension
  • Patented Anti-Rotation Tether — boot-link system
  • 3-piece Tele-Tri Patella Cup — Nylon 6, full kneecap coverage
  • Removable liners for sleeker fit option
  • Strap closure system — back A.R.C. cuff
  • Water resistant — non-corrosive metals, hand-washable soft components
  • Field-repairable design
  • Sizing: S (13"–14⅞"), M (14¼"–15¾"), L (15⅞"–16⅞"), XL (17"–18") knee circumference

Art of Racing is your European source for Asterisk knee braces. Ships from Europe.

Pairs Pair, Left, Right
Size Large, Medium, Small, X-Large
Fast deliveries

We ship worldwide every day via DHL. Delivery within the EU is typically 2–3 business days.

Free shipping over €150 in EU

We ship to every country DHL serves. Orders shipped to EU destinations qualify for free DHL shipping once the cart subtotal reaches €150. Orders shipped outside the EU are charged live DHL rates, calculated automatically at checkout.

30-day return policy

You have 30 days from delivery to return any item in original condition. Full policy →

Asterisk Technologies manufactures motocross knee braces designed for competitive off-road riding. The Cell and Ultra Cell series feature a polycentric hinged design that mirrors the natural flexion arc of the knee joint and includes an anterior tibial restraint system to prevent hyperextension under impact.

Asterisk braces are CE Level 1 certified and designed to be worn directly over base layer or under riding pants without requiring additional strapping systems. The polycentric hinge allows full range of motion in the riding position while the restraint geometry limits the joint angles associated with ACL and PCL loading under crash conditions. Sizing is based on knee circumference for correct hinge axis alignment.


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