Magazine - Czech"Duo", auto-loading, 6.35mm pistol, Serial number # 98417. The DUO holds 6 rounds in its magazine. Most likely made during the German occupation of Czechoslovakia. The DUO is a single action pistol virtually identical to the original Browning-designed Colt .25 hammerless vest-pocket model, which was introduced in 1908, and to which a magazine safety disconnector was added in 1917. The DUO eliminated the grip safety but retained the magazine disconnector. Like the Colt, it is a true hammerless pistol. The DUO has a groove down the top of the pistol, like the Colt and the CZ 45, but no other sights. (The Colt actually has minimalist sights in the groove.)