This pistol and black leather flap holster are pictured on page 12 of "The Deringer in America Volume II" by Eberhart and Wilson an noted as a "Unique 5-1/2 inch barrel pistol by Henry Deringer; on stock and mountings normally used on small pocket-size arms (for 2-1/2 inch barrel). The barrel is octagon and then becomes round forward of the forend; note unusual relief configuration at that point. .36 caliber, rifled. Accompanied by rarity of leather holster, made for this pistol specifically. Norm Flayderman collection."