psi
Pounds per square inch

in
H2O Inches of water column

oz/in2
Ounces per square inch

mBar
Millibar

Bar
Bar

mm
Hg Millimeters of Mercury (Torr)

in
Hg Inches of mercury

kgf/cm2
Kilograms force per square centimeter

KPa
Kilopascals

ft
H2O
feet of water column

Atm
Atmospheres