Chevrolet 2003 Impala Owner's Manual page 37

Safety Belt Extender
If the vehicle's safety belt will fasten around you, you
should use it.
But if a safety belt isn't long enough to fasten, your
dealer will order you an extender. It's free. When you go
in to order it, take the heaviest coat you will wear, so
the extender will be long enough for you. The extender
will be just for you, and just for the seat in your
vehicle that you choose. Don't let someone else use it,
and use it only for the seat it is made to fit. To wear
it, just attach it to the regular safety belt.
4. Buckle, position and release the safety belt as
described in Rear Seat Passengers on page 7-25.
Make sure that the shoulder belt crosses the
shoulder.
To remove and store the comfort guides, squeeze the
belt edges together so that you can take them out of the
guides. Pull the guide upward to expose its storage
clip, and then slide the guide into the clip. Turn the guide
and clip inward and in between the seatback and the
interior body, leaving only the loop of elastic cord
exposed.
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