Standard Air Knife The Standard Air Knife provides a quiet, hard-hitting curtain of air to clean, dry or cool parts, webs or conveyors. Using a small amount of compressed air as a power source, the Standard Air Knife pulls in large volumes of surrounding air to produce a high flow, high velocity curtain of air for blowoff. The Standard Air Knife dramatically reduces "wind shear" by gradually introducing the entrained air to the ejected compressed air, providing up to a 10 dBA noise reduction. Overall length is 1" (25mm) longer than the airflow length.