KETT Transformer Needle .4mm: This essential replacement part of the airbrush is responsible for mixing of paint with air and forming a spray pattern. Located inside the center of the airbrush (Part 25), this size needle is compatible with our Transformer Airbrush .4mm. The needle tip is fragile and can easily bend during cleanings. If this happens, the airbrush may not allow product to flow or the spray pattern may be irregular. This size needle is ideal for beauty to body makeup applications, or working with alcohol mediums and mediums with mica.