These brass shoulder scales were worn during the Civil War period as a dress distinction on the uniform coat & jacket of enlisted men. They were never worn on the sack coat. They are attached to the uniform by a tongue on the bottom of the scale, which slides through a brass attachment sewn on the shoulder of the uniform coat which is called a scale slide. At the collar is a second piece called the scale button which turns & locks the scale on the uniform. Sold in pair.