Alpinestars Nucleon KR-2i Men's Road Back Protector Insert, Black, Medium Founded in 1963, Alpinestars has built a reputation of innovation and prestige. Now, fifty years later, Alpinestars is synonymous with quality, protection, technology and style. CE certified Level 2 (EN1621-2:2014). Lightweight, flexible polyurethane-injected impact foam. Contoured for anatomical and adaptive fit.