Hummer 2009 H3 Owner's Manual page 42

1-38 Seats and Restraint System
1.3. Route the top tether
according to the child
restraint instructions and the
following instructions:
If the position you are using
does not have a headrest or
head restraint and you are
using a single tether, route
the tether over the seatback.
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.