These identification disks were the predecessors of the modern day "Dog Tag". Due to the poor record keeping of the era, and the fear of going unrecognized in death and the horror of war, these identification disks served a very useful purpose.
This particular disk is known as the "War of 1861" style. Made of brass. 28mm in diameter. Fabulous antique brass with mellow patina. The disk is in wonderful condition as evidenced in the photos.
The ID disk is marked: The front reads, War of 1861 United States and the back reads, David Bickford, Co. I, 15th Reg, NHV, Rochester NH.
David Bickford served in the Union Army from October 1862 to August 1863