Safety Belt Extender - GMC Sierra 2008 Owner's Manual

To make the belt shorter, pull its free end as shown
until the belt is snug.
Buckle, position, and release it the same way as the
lap part of a lap-shoulder belt. If the belt is not long
enough, see Safety Belt Extender on page 1-35.
Make sure the release button on the buckle is positioned
so you would be able to unbuckle the safety belt
quickly if necessary.

Safety Belt Extender

If the safety belt will fasten around you, you should
use it.
But if a safety belt is not long enough, your dealer/retailer
will order you an extender. When you go in to order it,
take the heaviest coat you will wear, so the extender will
be long enough for you. To help avoid personal injury, do
not let someone else use it, and use it only for the seat it
is made to fit. The extender has been designed for adults.
Never use it for securing child seats. To wear it, attach it
to the regular safety belt. For more information, see the
instruction sheet that comes with the extender.
1-35