RUSSIA, Union of Soviet Socialist Republics. 1923-1991. Uniface AV Octagonal Ingot (22mm, 9.98 g). Leningrad mint. Struck 1924. ПРОБА :/999 in two lines in incuse rectangle; below, М.Д. in incuse rectangle / Blank. Spassky, fig. 205 (second example). EF, traces of luster.
From the collection of Dr. Lawrence A. Adams. Ex World-Wide Coins of California (James F. Elmen) XIII (5 May 1988), lot 625.
According to Spassky, these ingots were issued for technical purposes, and not as payment.