Buick 1998 Century Owner's Manual page 63

A booster seat (F, G) is designed for children who
are about 40 to 60 lbs. (1 8 to 27 kg) and about four
to eight years of age. It's designed to improve the
fit of the vehicle's safety belt system. Booster seats
with shields use lap-only belts; however, booster
seats without shields use lap-shoulder belts.
Booster seats can also help a child to see out
the window.
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