Norrøna D3O removable Back Protector is a removable back protector designed for the Skibotn 15L pack and the Fjørå 18L pack.

The protector uses the core-patented D3O® technology, which is based on non-Newtonian principles. Under normal conditions the polymer chains flow freely, allowing the material to remain soft and flexible. Upon impact, however, they lock together and disperse the force energy, reducing the force that is transferred. This event lasts a few milliseconds, after which the polymer immediately returns to its flexible state.

The patented D3O® technology incorporates this non-Newtonian principle into other polymers for a rate-sensitive solution.