Hummer 2009 H2 - Manual (Page 328)

First Aid Kit and Tool Kit
If the vehicle has a first aid and tool kit, it is located in
the storage bin behind the spare tire on SUV models.
It is held in place with a hook and loop fastener strap.
On SUT models, the kit is in the rear cargo compartment
on the passenger side of the vehicle.
The kit includes a first aid kit, a flashlight, a tire pressure
gage, and a multi-purpose tool set.
The tire pressure gage has a reset button in the gage
stem. After taking a pressure reading, press the
button to reset the gage to zero.
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