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).
Torrs
The torr is named after Evangelista Torricelli, an Italian physicist who invented the barometer. One torr is the pressure of a 1 millimeter column of mercury at 0 degrees Celsius.