I just bought a used car with pull-up head supports. How should I adjust these to get the best head and neck support?

These restraint units are designed to help reduce the forces on your head and neck in the event of a rear-end collision. When the supports are adjustable, it is best to move them so they are as far forward as necessary to come in contact with your head and neck. They should be adjusted up or down so that they are slightly above your ear level.