The Longines 342 watch movement is an automatic mechanism developed in collaboration with Doxa, Eberhard, Favre-Leuba, Girard-Perregaux, and Zodiac. Utilizing a ball-bearing rotor, this movement features two roller freewheels and a worm screw regulation gear. It belongs to a family of movements based on the manual wind calibre AS 1687/1688. The specific differences between the 42.0, 42.1, and 42.4 models are not known. Functionally, this movement offers automatic winding, a sweep second hand, a date function set through a 20:40-24h adjustment, and a hack feature. It was predominantly used around 1970.