What collar device is worn by a Master Gunnery Sergeant?

The collar device worn by a Master Gunnery Sergeant features three stripes over a bursting bomb, accompanied by four rockers. This insignia is significant as it symbolizes the rank and responsibilities of a Master Gunnery Sergeant, which is a senior enlisted rank in the Marine Corps. The three stripes indicate the level of leadership and experience attained, while the bursting bomb represents specialty and technical expertise within their field. The additional four rockers further emphasize the seniority associated with this rank compared to other enlisted ranks. Each element of the device serves to distinguish the Master Gunnery Sergeant's level of accomplishment and role within the Marine Corps structure.