Toyota 2011 Matrix Owner's Manual page 313

3-6. Using the storage features
CAUTION
■
Caution while driving
Keep the auxiliary boxes closed.
Injuries may result in the event of an accident or sudden braking.
■
Items unsuitable for storing (overhead console only)
Do not store items heavier than 0.4 lb. (0.2 kg).
Doing so may cause the auxiliary box to open and the items inside may fall
out, resulting in an accident.
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Auxiliary boxes