These were more similar to officer's insignia, easier to read, and allowed a number to be placed on the disk. This might have been the 345th Infantry Regiment if worn with an infantry disk on the opposite collar or it might have been the 345th Field Artillery Regiment if paired with an artillery disk.
The infantry disk might have the company letter below the branch device.
The original concept of the bronze collar disks was that they would be worn on the service uniform as distinct from the blue dress uniform. Although, I do not find this classification system totally satisfactory, it is understood by collectors and therefore I will use it. The type classification is one by formulated collectors and not by the U. Edwards and the classification was extended and codified by James Mc Duff.This type was in use from 1910-1924 and was the type used during the First World War.They have a background pattern that was plain or may be dots, cross-hatches, diamonds, etc.For those who find that odd, I am only following established terminology that insignia collectors use. Forest Service, the Civilian Conservation Corps and others.