Alpinestars Nucleon Kr-Celli back protector insert L, Transparent Smoke — CE Level 1, ventilated honeycomb polymer

The Alpinestars Nucleon Kr-Celli Back Protection Insert in Transparent Smoke (Size L) is a CE Level 1 certified, lightweight polymer back protector designed to absorb impacts while remaining flexible and well-ventilated for active riders.

Built to blend protection with comfort, the Nucleon Kr-Celli insert uses a honeycomb polymer structure and ergonomic shaping to follow body movement inside compatible Alpinestars jackets and suits. Its translucent smoke finish keeps a low-profile look while the ventilation channels and flexible construction reduce bulk and heat buildup during long rides or aggressive track sessions.

How does this back insert protect me during a fall?

The Nucleon Kr-Celli meets CE Level 1 standards for energy absorption, meaning it reduces and distributes impact forces to lower the risk of injury to the spine area. Its polymeric construction deforms on impact and then returns to shape, combining shock management with reusability for everyday riding.

• CE Level 1 certification for verified impact absorption
• Honeycomb polymer structure disperses energy across the surface
• Designed to resist deformation while absorbing force

Will it be comfortable for long rides and active movement?

Yes — the insert is engineered for flexibility and low weight so it adapts to natural rider motion without creating pressure points. The ergonomic profile and flexible cells help maintain a close fit while allowing torso bending and twisting.

• Lightweight polymer reduces fatigue when worn for hours
• Flexible honeycomb units move with the body for less restriction
• Ergonomic shaping improves fit inside compatible garments

How does ventilation and heat management work with this insert?

Built-in ventilation channels in the honeycomb pattern promote airflow between the rider and the protector, helping heat and moisture to escape. This allows more consistent comfort in warm conditions compared with solid foam inserts.

• Open-cell/honeycomb design encourages air circulation
• Translucent material maintains slim profile for breathability
• Less trapped heat than traditional solid protectors

Can I use this insert with my current Alpinestars jacket or suit?

The Nucleon Kr-Celli is designed for compatibility with select Alpinestars jackets and racing suits that accept back protector inserts. Check your garment’s pocket size and manufacturer recommendations to confirm fit and positioning.

• Intended for Alpinestars garments with back-protector pockets
• Size L fits larger back pockets — verify measurements before purchase
• Easy to insert and remove for cleaning or swapping out

Who is this for: The Alpinestars Nucleon Kr-Celli back protector in size L is suited to sport and touring riders who want certified spine protection without bulk. It’s ideal for motorcyclists who prioritize flexibility, airflow, and a low-visibility look in a protector that integrates with compatible Alpinestars apparel. Choose this insert if you need a lightweight CE Level 1 shield that balances impact performance with everyday comfort.