This is a 4” 36 caliber Spur Trigger percussion revolver with assembly number 18 and all matching numbers. This is the later model with the single screw side plate. The mechanical function is very good crisp and tight. The bore is about very good bright and shiny with only a trace of old corrosion. It retains 80% nickel finish. About 700 were made in the 1850s to early 1860s.