The Aperture nozzle reduces exposure of the lens to air-born debris as well as directing airflow from the Air-assist accessory.
The nozzle is made of a flexible but durable silicone elastomer, this flexibility prevents damage to the Laser Unit if the nozzle crashes into something within the workspace. However if it is knocked or otherwise dislodged it will need to be correctly reattached and aligned as seen in the diagram.
