The First Years True Fit si C680 Instruction Manual page 9

Section 4 - Use Recommendations
C680 True Fit si Convertible Seat Forward Facing
Use Requirements:
This child restraint, with the upper seatback installed in a
forward facing position, is designed for use by children whose:
- Weight is between 23 and 65 lbs (10,43 and 29 kg), and
- Height is 50 inches (127 cm) or less.
- Age is 1 year.
Child MUST meet ALL of these requirements to use this
Convertible Seat forward facing.
Max
Ear
Height
WARNING !
NEVER install the C680 True Fit si in a forward
facing position without the upper seat back installed.
Upper
Seat
Back
Forward Facing
Use
23 - 65 lbs.
Less than 50"
Over 12 mos.
8