Developed around 1915, the Adler or Haeussler pistol is a straight blowback semi-automatic using a proprietary 7.25mm cartridge and a hinged dust cover assembly for easy field stripping and cleaning. Only approximately 100 of these pistols are believed to have been made. Mechanically, the pistol shows a strong resemblance to the work of Hugo Borchardt and Georg Luger, especially in the sear striker assembly, the overall shape of the frame and the grip angle. Blade front and notch rear sights, with a tapered barrel, safety switch on the left side of the frame, and "PATENT HAEUSSLER/ADLERWAFFENWERK/ENGELBRECHT & WOLFF" on the right side. Numbers match on the frame, barrel, top cover and bolt. With a pair of checkered grips with imprinted eagle designs. Included with the pistol is a hardwood presentation case, one extra magazine, one round of ammo, a cleaning rod, and papers.

Very fine, with 95% of the professionally restored blue finish, showing small areas of gray and brown patina, bright edge wear and mild spotting and handling marks. The grips are fine, with minor scuffs and dings. Mechanically excellent. The case is very good and shows mild wear.