Chevrolet 2005 T-Series Owner's Manual page 31

A forward-facing child seat (C-E) provides restraint for
the child's body with the harness and also sometimes
with surfaces such as T-shaped or shelf-like shields.
A booster seat (F-G) is a child restraint designed to
improve the fit of the vehicle's safety belt system.
Some booster seats have a shoulder belt positioner,
and some high-back booster seats have a
five-point harness. A booster seat can also help a
child to see out the window.
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