The locking clip prevents the seat belt from moving and provides improved stability when used with your child restraint / Car seat.
To achieve a secure install follow these steps:
Some car seats have a lock-off attached to a string that works in the same way. These need to be placed within 1cm of the latch plate (the same as locking clips above).
Note: Use only with child harness or with child restraint, color may vary from image.