Hummer 2010 H3 - Manual (Page 102)

3-58 Seats and Restraints
If the position you are using
does not have a headrest
or head restraint and you
are using a dual tether,
route the tether over the
seatback. If the position you are using
has a fixed headrest or
head restraint and you are
using a single tether, route
the tether over the headrest
or head restraint. If the position you are using
has a fixed headrest or
head restraint and you are
using a dual tether, route
the tether around the
headrest or head restraint.
3. Push and pull the child restraint
in different directions to be sure
it is secure.