Colt .22-45 Conversion Unit MFG:1970's
This Colt 22 Conversion Kit was believed to be built somewhere in the 1970's based on the box and it's used on accompanying government models. It has a fixed front sight, and fixed rear sight.
The end tag on this box is a bit odd, as this may have come from Colt as a take off from an assembled pistol. The end tag reads "22 Cal Kit as New".