What is the collar device for an E-3 in the Navy?

The collar device for an E-3 in the Navy is represented by three silver diagonal stripes. This distinctive insignia indicates the rank of Seaman, which is the title given to sailors holding this level of enlisted rank. The use of diagonal stripes on the collar reflects a system of insignia that visually conveys rank and hierarchy within the Navy. This particular design helps to ensure that personnel can be easily identified by their rank, facilitating order and structure in naval operations.

The other options refer to insignia associated with different ranks or roles within the Navy, which is why they do not apply to the E-3 rank.