pound force per square inch
Pound force per square inch (psi) is the pressure from a force of one pound-force on an area of one square inch, which is about 6,894.76 pascals. Car tires in the United States are typically inflated to 30–35 psi.
Inches of Mercury
Inches of Mercury (inHg) are used to measure pressure in the imperial system. Traditionally this unit is used in the United States for barometric pressure in weather reports. It is the pressure from a column of mercury exactly one inch high at standard gravity.