Historical unworn amber silver rings with their original tag. Found in an old box during house renovation on the Baltic Sea coast and dating back to the interwar period (1919-1939). The labels read: Silber, Garantierter Naturbernstein; Echt Silber, Echt Bernstein; 830/000 Silber, Naturbernstein

Likely from the SBM: The State Bernstein Manufactory Königsberg (SBM) , based in Königsberg (East Prussia), was founded in 1926 with the significant participation of Preussag AG and initially operated as "State Bernstein Manufaktur GmbH". The company existed until 1945 and temporarily employed up to 1500 people. It was the largest amber factory in the world at the time.