Buick 2005 Terraza - Manual (Page 38)

The third row (if equipped) has one guide for each
outboard position. To provide added safety belt comfort
for children who have outgrown child restraints and
booster seats and for smaller adults, the comfort guides
may be installed on the shoulder belts. Here is how
to install a comfort guide and use the safety belt:
1. Remove the guide from its storage pocket on the
side of the seatback.
2. Place the guide over the belt and insert the two
edges of the belt into the slots of the guide.
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