Alpinestars Nucleon KR-CELLi Back Protector • The triple segmented back shell plate constructed of a polymeric material blend. • Unique cell micro-structure designed for advanced energy absorption, adaptivity, maximum breathability and air flow. • Ergonomic protection plate contours to the natural curve of the back. • Horizontal flexion groves for an adaptive fit in different riding position. Available in multiple sizes and/or colours — select your variant.