Asterisk Motocross Knee Braces: Carbon Cell Pro, Carbon Cell 1, Ultra Cell 4.1, Micro Cell & MX Knee Protection | BTO Sports

Made in America.
Worn by Pros.

Asterisk traces its roots to the CTI custom knee brace, and the current lineup was relaunched in 2017 by former AMA Pro rider Mike Beier, who rebuilt the product from the ground up to address the fit and performance issues of the previous generation. Today Asterisk makes knee braces from aerospace and military-grade carbon fiber, all manufactured in the United States, and the brand is also the organization behind the Asterisk Mobile Medical Center that provides emergency care at AMA Supercross and Pro Motocross events. At BTO Sports, we carry the Asterisk Carbon Cell Pro, Carbon Cell 1, and Ultra Cell 4.1.

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Why we like Asterisk

Asterisk builds some of the lightest knee braces available in motocross, and the Carbon Cell Pro at roughly one pound per brace is the standout in a category where weight adds up quickly over a full day of riding. The aerospace carbon construction is not marketing language here: these are made from the same material grades used in aerospace and military applications, manufactured in the United States. The Asymmetri-Glide hinge tracks the natural rolling-gliding motion of the knee joint, and the anti-rotation tether connecting the brace to the boot addresses a specific injury risk that standard hinged braces do not. Asterisk also runs the Mobile Medical Center at AMA professional events, which means the people designing these braces work with motocross injuries professionally, not just theoretically. That hands-on medical involvement is something no other knee brace brand can claim, and it shows in how the product is designed.

FAQ

  • The Carbon Cell Pro is the flagship, built from aerospace-grade carbon fiber prepreg at approximately one pound per brace, making it the lightest option in the lineup with a custom-feeling fit from an off-the-shelf product. The Carbon Cell 1 uses military spec and aerospace-grade carbon fiber and is also made in the USA, offering an ultra-light build with broad pressure distribution across the hinge for a neutral feel against the bike. The Ultra Cell 4.1 is a refinement of Asterisk's original Cell design with more than ten years of development behind it, using a carbon fiber epoxy matrix frame with full-coverage patella cup and a brace-to-boot tether attachment.

  • Asterisk braces are sized by circumference measured directly on the skin at the middle of the kneecap with the leg straight. Sizes run XS through L. The A.R.C. cuffs on the Carbon Cell Pro are adjustable at both the thigh and calf for a customized fit while maintaining frame rigidity. Measuring carefully is important because a properly sized brace distributes pressure broadly across the leg rather than creating pressure points. Asterisk's sizing chart is available on our BTO Sports product pages and should be used rather than converting from apparel sizing.

  • The Asymmetri-Glide hinge is designed to track the knee's natural rolling-gliding motion rather than a simple pivot. The knee does not hinge on a fixed point during flexion and extension, it actually shifts as the joint opens and closes. Traditional flat hinges do not account for this movement and can create friction or unnatural load on the joint. Asterisk's Asymmetri-Glide uses an anatomically correct hinge profile in aerospace carbon fiber, and the asymmetrical design on each side allows the lower frame to align automatically with the tibia for a more accurate fit to the leg's actual movement pattern.

  • The anti-rotation tether is a patented connection between the brace and the boot that resists rotational forces on the lower leg during a crash. A significant number of knee and lower leg injuries in motocross come from the lower leg twisting independently of the upper leg when a rider goes down. Standard knee braces protect against hyperextension and varus or valgus loads but do not address this rotational risk. The tether prevents the tibia from rotating excessively relative to the femur, which reduces the chance of ACL and meniscus injuries from that specific type of impact.

  • The Leatt C-Frame is a premium single-sided brace with a thin hinge profile and wide pressure distribution that many riders favor for its natural bike grip feel. It is also one of the more expensive options in the category. The EVS RS9 is a solid rigid brace at a lower price point with good protection credentials and strong value. Asterisk sits at the top of the market in terms of materials quality and US manufacturing, and the Carbon Cell Pro's weight advantage over both is meaningful for riders who are brace-conscious about fatigue on long motos. The anti-rotation tether is a feature neither Leatt nor EVS offers as a standard part of their system.

  • The Asterisk Mobile Medical Center is a full emergency care facility that Asterisk operates and deploys at AMA professional Supercross and Pro Motocross events. It is staffed with qualified medical personnel and carries equipment specifically selected for the types of injuries common in motocross racing. This program is unique to Asterisk in the brace market and means the people running the company work directly with crash injuries at the highest level of the sport, week after week during the race season. That clinical exposure directly informs how their protection products are designed and refined.

  • Yes. The Carbon Cell 1 is built from military spec and aerospace-grade carbon fiber prepreg manufactured in the United States, and the rest of the Carbon Cell lineup follows the same domestic production approach. For riders who prioritize US manufacturing in their gear purchasing, Asterisk is one of the very few motocross brands that can make that claim authentically on their primary products.

  • The Ultra Cell 4.1 includes a brace-to-boot tether attachment, and the tether system is designed to work with most standard MX boot designs. Some bulkier boots with wide upper cuffs may fit differently with the brace frame, and riders should check that the lower brace cuff sits properly above the boot's ankle closure before riding. The Carbon Cell Pro and Carbon Cell 1 are designed to fit over or around most boots without significant interference. If you have questions about compatibility with a specific boot model, reach out to our BTO team and we can help.