The U.S. Navy has clearly defined regulations regarding uniforms and wearing collar devices. These regulations depend upon whether the person wearing the uniform is an officer or is enlisted. Officers and enlisted personnel wear different uniforms, each with their own regulations and collar device requirements. Officers are further divided, with separate uniform regulations, between line officers or staff corps and include limited duty officers and warrant officers.
Navy Uniform Regulations
Navy uniform regulations are available online. They cover each type of uniform: officer or enlisted, male or female and each groups' various dress and work uniforms.
Collar Device Locations
The Atlanta COA uniform guidelines say collar devices must be centered 1 inch down from the upper edge of the right collar and 1 inch in from the leading edge. The device should be parallel to the leading edge of the collar.
Public Health Service (PHS) Corps
PHS Corps device is worn on the left collar point in the same manner as the rank device.
The Bluejackets' Manual
The Bluejackets' Manual, available through the Navy Exchange, gives practical guidelines for uniform wear based on Navy regulations. It also gives information regarding the ranks and uniform designations of the other armed services.
The practical last word on uniforms is to ask at the Base Exchange Uniform Shop for any questions regarding the correct way to wear your uniform or any appropriate insignia.