During the years of World War I, the production of small souvenirs became unusually widespread among soldiers. Rings in particular became extremely popular in this respect, as they not only served as a personal souvenir but also represented a valued trade item. Today, most collectors think of a trench ring as a hand-hammered aluminium casting with engraved dates. However, the range of soldier-made rings was much wider. Virtually forgotten today are rings and bracelets knitted from horsehair and glass beads. This technology was probably a specific concern of Russian prisoners of war, who were reacting to the shortage of aluminium in the Austro-Hungarian prison camps. The finished product was usually intended to be exchanged for food with the local population.