Issued in every command post and training center of the Civil Guard until the mid-1970s, when it was replaced by the MG-42. It was 7.62 mm (0.3") caliber and was a modified version of the light machine gun created in Oviedo in the mid-1940s: the Alfa Model 1942 (7.92 mm (0.31") caliber, based on the Czech ZB-37). Four of these Alfa 55 machine guns were issued to the first Mobile Unit of the Civil Guard in Equatorial Guinea.