Full-Length Impact Protection with Breathable Comfort

The Alpinestars Nucleon Flex Proi offers full-length back protection (approximately 22% longer than standard inserts) combined with exceptional ventilation and flexibility. Designed specifically as a high-performance insert for compatible Alpinestars sport and touring jackets released since Spring 2022, it delivers superior safety without compromising rider comfort.

Protection

• Certified to EN 1621‑2:2014 Level 2 (T+ & T‑) for elite impact absorption.

• Hybrid construction of Nucleon Cell (central rigid core) and Nucleon Flex (surrounding flexible zones) optimizes force dispersion and flexibility.

• Snap button compatibility ensures secure fit in Alpinestars jackets.

Material

• Lightweight polymeric shell with varying rigidity firm in the center, more flexible at the edges for anatomical conformity.

• Soft and breathable 3D mesh lining next to the body supports airflow and prevents overheating

Comfort

• Available in three waist-to-shoulder sizes (S/M/L) to fit a wider range of body types comfortably.

• Designed with ergonomic contours that flex with rider motion—ideal for touring or sport riding.

• Extremely lightweight and well-ventilated, minimizing bulk and heat buildup

Cautions

• Limited to Alpinestars jackets with dual-size back protector pockets (post Spring 2022 models). Not compatible with older or non‑Alpinestars gear.

• Some users report sizing confusion—ensure correct waist‑to‑shoulder measurement to achieve full coverage

• While user impressions vary some preferring D3O or Forcefield offerings for perceived structure this protector meets strict CE Level 2 standards