The firearm shown is a classic Walther PP semi-automatic pistol, serial number 390705, chambered in the popular .32 ACP (7.65mm) caliber. This specific example appears to be a wartime production model, identifiable by the "ac" manufacturer code which indicates production by the Carl Walther Waffenfabrik factory in Germany, likely for police or military use. Known for its quality construction, reliability, and innovative double-action design, this pistol is a sought-after collector's item.