Hummer 2008 H2 - Manual (Page 11)

Head Restraints
Adjust the head restraint so that the top of the restraint
is at the same height as the top of the occupant’s
head. This position reduces the chance of a neck injury
in a crash.
Pull the head restraint up
to raise it. To lower the
head restraint, press
the release button,
located on the top of
the seatback, while
you push the head
restraint down.
The second and third row seats have head rests that
can be adjusted up and down.
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