GMC 2004 Savana - Manual (Page 49)

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.
1-43