• Developed in three waist-to-shoulder dimensions to cover all body sizes
• High performance polymeric material Cell and Nucleon Flex structures for optimized flexibility and excellent weight saving properties
• The back protector's design changes from the center towards the outside, providing a balance between energy absorption and flexibility
• Soft, comfortable 3D mesh on the body side of the protector offers breathability and rider comfort
• Snap button compatibility for quick and easy use with Alpinestars suits and jackets
• Rigorously tested and certified to T+ & T for proven performance in extreme temperatures
• Back Protector: EN 1621-2:2014 Level 2 (T+ & T-)

The Alpinestars Nucleon Flex Pro Back Protector Insert delivers full-length Level 2 protection in a lightweight, insert-style design. Built using a hybrid of Nucleon Cell and Nucleon Flex technologies, it balances effective impact force dispersion with flexibility and reduced weight. Approximately 22% longer than standard inserts, it offers extended coverage similar to a fixed back protector while maintaining everyday practicality. Designed to fit Alpinestars sport and touring jackets released since Spring 2022, the Nucleon Flex Pro integrates easily into dual back protector pockets. An adaptive structure improves energy absorption where needed while preserving mobility, and a soft-touch 3D mesh liner enhances airflow and comfort. Certified to EN 1621-2:2014 Level 2 (T+ & T-), it provides dependable protection without added bulk.