This layer is not always a soft one either. In some cases, soft material like flannel can trap dirt which abrades the surface. In the case of a soft varnish, soft cotton can actually get embedded into the surface. Some examples of protective wrap include natural and synthetic papers, plastic sheet, and cloth. This layer provides protection from damaging bumps and repeated small impacts.
Elastic memory allows the cushioning effect to occur as often as necessary.
Sudden blows to this packing layer are distributed throughout, and little of the force is transferred to the packed item. The cushion material is usually a foam or rubber composition. Vibration can be simply defined as small impacts, repeated at intervals and over an extended period. Vibration may seem innocent because of the small size of force involved, but it can literally shake the paint off a surface. Small cracks can spread due to prolonged vibration.