Norrona’s removable back with its D3O® core patented technology is based on non-Newtonian principles, which is one of the more advanced features in modern ski accessories. In standard conditions, the polymer chains on a Non- Newtonian fluid flow freely, allowing the material to remain soft and flexible, but on the impact, they lock together dissipating the impact energy and reducing the force transmitted. This event lasts milliseconds; the polymer then instantly returns to its flexible state. The D3O® patented technology incorporates this Non- Newtonian practice into other polymers for a rate-sensitive solution.