What is active headrest?
If the headrests on your seats look like they're made by two joint pieces, they're most likely active headrests. Although some of the active headrests are in 'one-piece-design', they still have the 'active' feature.
An active head restraint (or headrest) moves forward and upward in a rear-end collision to decrease the space between the restraint and the occupant's head, reducing the degree to which the head accelerates before making contact. The less acceleration, the lower the chance of injury.
Why choose active headrest?
Using a lever-action mechanism built into a seat, the active headrest redirects the force of an occupant's body as it presses into the backrest to move the head restraint forward. The beauty of this design is that it reacts proportionately to the occupant's motion. Unlike the type of pyrotechnic charge used in airbags and seat belt pretensions — the intensity of which may be too high or low - the active head restraints' motion is dictated by the occupant's size and weight and the severity of impact.
Another reason is that most clients do not want to damage the original headrest pillow,so Active Headrest DVD would be the perfect choice.
source from http://www.cardvdonline.com