GMC 2005 Savana - Manual (Page 53)

Top Strap
Some child restraints have a top strap, or “top tether.”
It can help restrain the child restraint during a collision.
For it to work, a top strap must be properly anchored
to the vehicle. Some top strap-equipped child restraints
are designed for use with or without the top strap
being anchored. Others require the top strap always
to be anchored. Be sure to read and follow the
instructions for your child restraint. If yours requires that
the top strap be anchored, do not use the restraint
unless it is anchored properly.
If the child restraint does not have a top strap, one can
be obtained, in kit form, for many child restraints.
Ask the child restraint manufacturer whether or not a kit
is available.
In Canada, the law requires that forward-facing child
restraints have a top strap, and that the strap be
anchored. In the United States, some child restraints
also have a top strap. If your child restraint has a
top strap, it should be anchored.
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