Hummer 2005 H2 - Manual (Page 287)

First Aid Kit and Tool Kit
The first aid and tool kit 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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