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1. CE and UKCA Level 2 certified full-length back protection at £89.99 delivers the highest standard of back protector certification at a price that is very accessible for a Level 2 insert
2. At 22% longer than standard back protector inserts, the Proi covers the full thoracic spine zone that shorter inserts leave partially exposed — providing coverage equivalent to a dedicated standalone back protector in an insert format
3. Hybrid Nucleon Cell and Nucleon Flex technology combines the energy absorption of the Cell microstructure with the flexibility of Flex technology, providing full-length Level 2 protection in an insert that doesn’t stiffen the jacket
1. Compatible specifically with Alpinestars sport and touring jackets released since Spring 2022 that have the double pocket — owners of older Alpinestars jackets or other brand jackets should verify compatibility before purchasing
2. Three waist-to-shoulder dimensions require correct size selection; unlike fixed-shape inserts, length variation requires measuring against the size guide rather than going by the jacket size
3. Full-length insert format, while longer than standard, still represents an insert rather than the dedicated standalone back protector that some riders prefer for the most definitive fit assurance
Back protector inserts have traditionally presented riders with a choice between practicality and protection standard: short standard-length inserts fit easily but leave the lower back exposed, while full-length standalone protectors cover the full spine but add fitting complexity. The Alpinestars Nucleon Flex Proi Full Back Protector Insert resolves that trade-off with an insert that is 22% longer than standard alternatives, with CE and UKCA Level 2 certification across the full length.
The Proi’s construction uses a hybrid of two Alpinestars protector technologies: Nucleon Cell and Nucleon Flex. The outer shell is an ergonomically contoured dual-zone structure using a solid Cell core framed by a more flexible 3D Cell structure as the first protective layer. The Cell microstructure is designed for advanced energy absorption through the deformation and collapse of the cellular geometry during an impact, distributing the force laterally across the Cell network rather than transmitting it vertically through the spine. This outer layer is reinforced with a Nucleon Flex technology layer across the central back zone, providing additional energy dissipation and flexibility in the primary spinal impact area.
The combination delivers the force dispersion of Cell technology with the conforming flexibility of Flex technology, creating a full-length Level 2 protector that doesn’t create the rigid, movement-restricting feel of a solid Level 2 back panel. The protector is available in three waist-to-shoulder dimensions to match different body heights, ensuring the full-length coverage reaches from the tailbone area to the shoulder zone regardless of the rider’s proportions.
The body-contact face of the protector is lined with a breathable soft-touch 3D mesh that provides airflow and skin-touch comfort for extended jacket wearing. Snap button compatibility ensures quick and easy fitting to Alpinestars sport and touring jackets that feature the double back protector pocket released since Spring 2022.
The Nucleon Flex Proi is for riders with Alpinestars sport or touring jackets (Spring 2022 or later) who want to upgrade their jacket’s back protection to CE and UKCA Level 2 in a full-length format. It’s the right choice for riders who want the coverage of a fixed standalone back protector in the practical format of a removable jacket insert, and those who want Level 2 certification without the cost and complexity of a full external back protector system.
– CE Level 2 / UKCA certified: EN 1621-2:2014 Level 2 (T+ and T-)
– Full-length insert: approximately 22% longer than standard back protector inserts
– Nucleon Cell and Nucleon Flex hybrid construction
– Dual-zone outer shell: solid Cell core with flexible 3D Cell outer frame, reinforced with Nucleon Flex central layer
– Breathable soft-touch 3D mesh body-contact liner
– Available in three waist-to-shoulder dimensions
– Snap button compatibility for Alpinestars jacket fitment
– Compatible with Alpinestars sport and touring jackets from Spring 2022 onwards
– Certified for performance in extreme temperatures
The Nucleon Flex Proi at £89.99 is remarkable value for CE and UKCA Level 2 full-length back protection: the hybrid Cell-Flex technology, extended coverage, and snap-button jacket integration make this the most capable jacket back protector insert Alpinestars produce.
The Nucleon Flex Proi is the back protector insert for riders who want Level 2 certification and full thoracic coverage from their jacket insert. At £89.99 for CE and UKCA Level 2 with hybrid Cell-Flex technology and 22% extended length, this is genuinely excellent value for what it delivers.
1. CE and UKCA Level 2 certified full-length back protection at £89.99 delivers the highest standard of back protector certification at a price that is very accessible for a Level 2 insert
2. At 22% longer than standard back protector inserts, the Proi covers the full thoracic spine zone that shorter inserts leave partially exposed — providing coverage equivalent to a dedicated standalone back protector in an insert format
3. Hybrid Nucleon Cell and Nucleon Flex technology combines the energy absorption of the Cell microstructure with the flexibility of Flex technology, providing full-length Level 2 protection in an insert that doesn’t stiffen the jacket
1. Compatible specifically with Alpinestars sport and touring jackets released since Spring 2022 that have the double pocket — owners of older Alpinestars jackets or other brand jackets should verify compatibility before purchasing
2. Three waist-to-shoulder dimensions require correct size selection; unlike fixed-shape inserts, length variation requires measuring against the size guide rather than going by the jacket size
3. Full-length insert format, while longer than standard, still represents an insert rather than the dedicated standalone back protector that some riders prefer for the most definitive fit assurance
