Inches of water
Inches of water (inH₂O) is a pressure unit from the Imperial system. An inch of water is defined as the pressure from a one inch column of water at 4°C (39.2°F) (which is the temperature at which water is densest).
Kilogram force per square meter
Kilogram force per square meter (kgf/m²) is a unit from the force of one kilogram under standard gravity (9.80665 m/s²) on an area of one square meter.