The linear air gauging is effective without contact or with neglectfully force of measuring in accordance with the realized measuring head and is able to detect toleranz of fits with highest precision in obey the Abbe´s princip of comparator among rough conditions of manufacturing. The air pressure stearming of the measuring head is cleaning the measuring spot automaticly and take the actual dimension within the measuring range of the measuring head which is designed for. (DIN 2271 ff)