Chevrolet 1999 Monte Carlo Owner's Manual page 40

CAUTION:
You can be seriously hurt if your shoulder belt is
too loose. In a crash, you would move forward
too much, which could increase injury. The
shoulder belt should fit against your body.
To unlatch the belt, just push the button on the buckle.
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Rear Safety Belt Comfort Guides for
Children and Small Adults
Rear shoulder belt comfort guides will provide added
safety belt comfort for children who have outgrown
child restraints and for small adults. When installed on a
shoulder belt, the comfort guide pulls the belt away
from the neck and head.
There is one guide for each outside passenger position in
the rear seat. To provide added safety belt comfort for
children who have outgrown child restraints and for
smaller adults, the comfort guides may be installed on
the shoulder belts. Here's how to install a comfort guide
and use the safety belt:
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