The Fiala Model 1920 was a manually-operated repeating pistol in .22LR caliber that was marketed with the backing of famed polar explorer Anthony Fiala. The guns came as a set of one frame, three barrels (3", 7.5", and 20") and a removable shoulder stock. This allowed the owner to set the gun up in whichever configuration they liked (and it was before the NFA placed regulations on pistols with shoulder stocks). Today, these guns may still be used with the stock, as they have been specifically exempted from the NFA because of their historical and collectible value.
Mechanically, the Fiala is unusual because despite its appearance it is not a semiautomatic design. Instead, the shooter must manually operate the slide between shots. This made the gun less expensive to manufacture, and theoretically more reliable.
There are several lots of these Fialas available in the upcoming RIA auction; this particular one includes two frames, two 7" barrels, one 20" barrel, and one buttstock.