Pontiac 1998 Firebird Owner's Manual page 44

A booster seat (F, G) is designed for children who
are about 40 to 60 lbs. (18 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.
1-37