Developed as a counterpart for the Government Model/1911A1 pistol, the Ace conversion kit allowed for handgun training with the inexpensive 22 LR cartridge while preserving the larger pistol's handling and manual of arms. The Service Model upgrade integrated a floating chamber, boosting the recoil of the small round to be closer to the 45 ACP. The slide is parkerized, with the two-line Colt address and Service Model nomenclature on the sides, fixed front sight and adjustable square notch rear sight. The barrel, recoil spring assembly and magazine are blued, the latter also bearing Service Model markings. With a properly labeled Colt "wood grain" box and an instruction sheet for a later model Ace kit.