Developed around 1915, the Haeussler pistol is a straight blowback semi-automatic using a proprietary cartridge and a hinged dust cover assembly for easy field stripping and cleaning. Mechanically, the pistol shows a strong resemblance to the work of Hugo Borchardt and Georg Luger, especially in the exposed sear striker assembly, the overall shape of the frame and the grip angle. Blade front and notch rear sights, with a tapered barrel, light border engraving on the frame with the eagle logo, "ADLERWAFFENWERK, ZELLA ST./BL/" and "PATENT HAEUSSLER" on the right side of the frame. With a pair of checkered grips and a straw finished trigger.