Britax safe-n-sound BS4000A-020133 Manual Instructions For Installation & Use page 21

G. The seatbelt must fit firmly but comfortably across the lap and chest. If needed,
adjust the vehicle seat to improve the position of the sash on the child's chest.
It should pull to the rear of the child.
H. Always ensure the lap belt is on the child's hips and thighs at all times. The lap
belt must not be on the child's abdomen. The sash belt must be across the
child's chest.
IMPORTANT :
Always ensure the seatbelt is firmly fitted to the hips and thighs and the sash
belt is diagonally across the chest.
The SecureGuard™ Device correctly adjusted must always be used when the
child is using the booster seat as it ensures the lap belt is correctly positioned
on the child's thighs and hips. A loose or poorly positioned lap belt can allow
the lap belt to ride up into the abdomen and can cause serious injuries in a
crash.
DO NOT LEAVE CHILDREN UNATTENDED IN
THE CAR
Instructions for Installation & Use - Series No. BS4000A-020133
:
HOW TO USE
21