Toyota 2009 Tundra Owner's Manual page 442

3-6. Using the storage features
Rear door (type A)
Rear door (type B)
n Removing the hold separator (front bench type seat only)
CAUTION
When not in use (front bench type seat only)
n
Keep the bottle holders closed.
Injuries may result in the event of an accident or sudden braking.
418
Remove the hold separator.
Bottle holders