Alpinestars bionic mtb back protector bns incorporating design innovations from moto gp development and dynamic force dispersion technology dfd tech the bionic back protector offers ce level 2 protection in a slimline unobtrusive form for performance safety and comfort both on the road and on the track alpinestars bionic mtb back protector bns 2012 features ergonomic 5 plate construction contours to the natural curve of the back plates lock to prevent rear overextension of the back wide