The United States Navy

Enlisted members are said to be "rated", meaning that they possess a rating, or occupational specialty. Members of grades E-1 to E-3 can become "strikers", meaning they have rating designations like Petty Officer (example: a BM3 is a Petty Officer Third Class rated as a Boatswain's Mate; BMSN is a Seaman designated as a Boatswain's Mate striker), but the striker is doing on the job training to become a rated petty officer rather than attending a school to become rated. There are more than 50 ratings covering a broad range of skills and subspecialties. However most sailors in today's navy with grades E-1 through E-6 obtain their rating through its respective "A" school. An "A" school is a rating specific school where sailors are trained as experts in their field. Upon completion of their training they are considered "Rated", regardless of their pay-grade.
For example, SA SMITH, MARY, would be considered a Seaman Apprentice. Prior to her rank of SA a rating would be placed. Therefore, her entire title would be ITSA SMITH, MARY. IT indicating that she is an Information Systems Technician. As for ENFN THOMPSON, JOHN. EN specifying that he is an Engineman and FN as Fireman.
• Uniforms and appearance
The uniforms of the United States Navy are designed "to combine professionalism and naval heritage with versatility, safety, and comfort". The Navy currently incorporates many different styles that are specific for a variety of uses and occasions. In most cases, distinctions are made to distinguish officers and enlisted men in their uniformed appearance. U.S. Navy uniforms can generally be divided into three categories: dress uniforms, service uniforms, and working uniforms.