Final answer:
A Master Chief Petty Officer wears a fouled anchor insignia on their collar.
Step-by-step explanation:
A Master Chief Petty Officer in the military wears a collar insignia called a fouled anchor. The fouled anchor is a symbol of a senior enlisted rank in the United States Navy and Coast Guard. It consists of a gold anchor overlaid with silver-twisted hawser ropes, with the anchor's shank and the hawser ropes forming the shape of the letter 'M' for 'Master Chief.' This insignia is worn on the right collar point of the dress uniform and the right pocket flap of the working uniform.