Produced as an experimental prototype, the included factory letter states that this pistol was provided by Colt to the Federal Bureau of Investigation for testing purposes, most likely during the period of the 1980s when the Bureau considered the 10mm cartridge for standard issue. The feedback from these FBI tests led to the development of the modern 40 S&W cartridge. Equipped with 3-dot Trijicon night sights, checkered trigger guard, ring hammer, checkered flat mainspring housing and checkered Colt imprint grips. With Colt maroon box with hand marked end label.