Cosco Stack-It!, Quick Start Manual

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Troubleshooting

Do not use this booster 
seat if the tops of your 
child’s ears are above the 
top of the vehicle seat 
back or headrest.
Use only the vehicle’s lap 
and shoulder belt system 

when restraining the child in this booster 
seat. 
Check vehicle instructions for more 
information about air bag/booster seat 
use.

Do Not Use only the 
lap belt when using 
this seat. 
The shoulder belt 
must always be 
adjusted snugly 
across the child’s 
chest.  
NEVER place the 

shoulder belt behind the child’s back or 
under the child’s arms. 
Failure to follow these warnings could 
cause serious injury or death to your 
child.   

1.

 If the shoulder belt crosses the child’s 

neck when using the booster seat: 

Try moving the booster seat toward the 
center of the vehicle or move the vehicle seat 
forward or back.  Check to see if your vehicle 
has adjustable shoulder belt anchor points. 

WARNING: 

NEVER place the shoulder 

belt behind the child’s back.

By the nature of the design, backless 
booster car seats do not have a back 
or headrest. These types of booster 
car seats help position the vehicle belt 
across the body. 
Any additional protection of the body 
or head is dependent on the protection 
systems of your vehicle. 
Please consider this when choosing 
where this booster will be used in your 
vehicle and always consult your vehicle 
owner’s manual.