Britax PIONEER User Manual page 9

Booster Mode:
WARNING!
children who meet ALL of the following requirements. Use only the
vehicle's lap and shoulder belt to secure the child. If the child does not
meet all booster mode requirements because the child is too small,
you may need to use this child seat in harness mode. Thoroughly
review all fit requirements before using the child seat.
Children must:
1 weigh between 40 and 110 lbs (18.1 and 49.9 kg) and
2 stand between 45 and 62 in. (114.3 and 157.5 cm) in height
and
3 the top of the child's ears must be below the top of the head
restraint and
4 the shoulder belt must be appropriately positioned across the
center of the child's chest in the closest position at or above
the child's shoulder through the shoulder belt guide and
5 the lap belt is routed under the armrests, low across the
child's upper thighs.
NOTE: BRITAX recommends booster mode only after the child
outgrows harness mode.
Booster mode use of this child seat is ONLY for
Child Seat Fit Requirements
7