9. shot (n.) a consecutive series of pictures that constitutes a unit of action in a film
The vacuum level is determined by the pressure differential between the evacuated volume and the surrounding atmosphere. Several units of measure can be used. Most refer to the height of a column of mercury â usually inches of mercury (in.-Hg) or millimeters of mercury (mm-Hg).
Vacuum experts say that this is important to a vac's performance and so is water lift and brushroll speed, design, etc. The three act in tandem to clean. Most companies use a little trickery to brag about air flow and water lift. They are measured at the vacuum opening, not at the end of the nozzle/hose/etc. However, it remains a fact of nature that the higher the water lift and air flow numbers, the better it will perform with the filters, bag, and hose in place. You must have strong suction to lift dirt from deep in carpeting.