Vintage Tissot Antimagnetique (add more to comments below)
The Tissot caliber 27-1T was produced in Switzerland. The base caliber is a Tissot 27 which was released in 1936 and produced until 1949. Following 1949, many variations were introduced and manufactured until about 1961. The movement pictured here is a 27-1T, produced in circa 1950-1952. The 1T indicates that the movement is equipped with an Incabloc shock system.