Chevrolet 2008 Optra Owner's Manual page 29

Shoulder Belt Height Adjuster
Your vehicle has a shoulder belt height adjuster for the
driver and right front passenger.
Adjust the height so that the shoulder portion of the belt
is centered on your shoulder. The belt should be
away from your face and neck, but not falling off your
shoulder. Improper shoulder belt height adjustment
could reduce the effectiveness of the safety belt
in a crash.
After you move the height adjuster to where you want it,
try to move it down without pressing the release
button to make sure it has locked into position.
To move it down, press
the release button (A) and
move the height adjuster
to the desired position.
Safety Belt Pretensioners
Your vehicle has safety belt pretensioners for front
outboard occupants. Although you cannot see them,
they are part of the safety belt assembly. They can help
tighten the safety belts during the early stages of a
moderate to severe frontal or near frontal crash if the
threshold conditions for pretensioner activation are met.
Pretensioners work only once. If they activate in a
crash, you will need to get new ones, and probably other
new parts for your safety belt system. See Replacing
Restraint System Parts After a Crash on page 1-67.
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