On the booking page for your rental car, you can select one or more of the following.
Navigation
System (GPS)
Especially useful on Oahu
Infant Seat
Rear facing.
For infants 5-22 pounds
Toddler Seat
Forward facing.
For toddlers 22-65 pounds
Booster Seat
Required for children aged 4-7
Unless over 4'9"