Chevrolet 1995 Astro Cargo Owner's Manual page 42

Lap Belt
If your vehicle has rear bench seats, someone can sit in the center positions.
When you sit in a center seating position, you have a lap safety belt, which
has no retractor. To make the belt longer, tilt the latch plate and pull it along
the belt.
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 isn't long enough, see "Safety Belt Extender"
at the end of this section.
Make sure the release button on the buckle is positioned so you would be
able to unbuckle the safety belt quickly if you ever had
to.
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