This is a Colt .22 Conversion Unit with Floating Chamber and the instructions says Feb. 1951. The slide retains 97% original blue comes with barrel, floating chamber, ejector, recoil spring, magazine and slide stop. The mechanical function is very good and crisp. The box is in very good condition but is worn where the front sight and rear adjustable sight have worn on the inside of the box. The instruction sheet was taped on some of the folds where they were separating.