This is a very fine example of a very rare, very early Mauser Model 1914 "humpback" pistol with serial number "15". These "humpback" pistols were pilot models to test public acceptance of the new gun with the "humpback" style slide meant to differentiate this model from the Model 1910. Usually these pistols were fitted with a 3 1/2 inch barrel while this example has a slightly shorter 3 3/8 inch barrel that is correct and not altered as it still has the original early style milled front sight with no sight barrel band and a "V" notch rear sight. The "humpback" style slide was dropped sometime after reaching serial number 3,000; consequently, it is a very rare and highly sought after variations of the Mauser Pocket Pistols. The left side of the slide has the early three markings of: "Waffenfabrik Mauser A.G./Oberndorf a, N./Mauser's Patent", and below that it has the Mauser Banner. The serial number "15" is stamped only on the rear of the frame, and the barrel is serial numbered "59". It is fitted with finely checkered wrap around walnut grips and is complete with the early second pattern magazine with the square front base plate and the split "T" type rear section. It has the pre-war rust blue finish and a fire blue trigger and barrel retaining rod head. This wonderful early Mauser pistol is complete with a very rare original Mauser 4mm conversion barrel set. This set includes four separate machined chamber inserts (for the 4 mm cartridges) a spare magazine (original early second model), a cartridge ejector rod and an original Mauser long 4 mm barrel. The barrel is numbered "594" on the side of the lug, and it has the correct small narrow approximately 12 lands and grooves designed for the 4mm ball cartridges. This conversion kit also includes approximately 30 4 mm cartridges and 3 loose lead balls (bullets). The conversion kit and accessories are all contained in a newly manufactured walnut storage case.