Colt 3rd Model (Thuer) Derringer fires a .41 cal. rimfire cartridge and is so marked on the left side of the frame. On top of the barrel it is marked -COLT-. One derringer is factory silver plated (APPROX 65%) and the other is standard brass frame. There is no blue finish left on either barrel and there is slight pitting on the brass frame model. Both pistols come with very nice wood grips with no damage. The grips on the brass frame model may be very rare. Both pistols function as designed. The silver plated pistol has a serial # 8xxx and the other is #28xxx. $400 Sold silver plated pistol, one left.