This is the first of the Star SMGs to reach widespread service. It was the standard Army weapon for several years before being largely replaced by the Z-62 weapons. It is almost identical to the German MP40 SMG, differing only in that the Z-45 has wooden grips, a barrel shroud, a quick-removable barrel, the bolt handle on the right, and the weapon is selective fire (by means of the dual-pulling trigger later seen on the Z62). Some were also made with a fixed wooden buttstock. Beside the Spanish Army service this weapon was sold to Chile, Cuba, Portugal and Saudi Arabia in quantity, and smaller volumes to numerous other locales. Due to the longevity of such overbuilt weapons, and spreading sales on the secondary market, they may be encountered almost anywhere in the world today.
This seems to have been a high quality, almost first-generation sub-machine gun, in the sense of the original Thompson. They are all well-finished, have decent sights with some adjustment, have excessive machining of parts that don't really need it, and all seem to be equipped with a muzzle compensator.
Firearms marked 9 mm / 38 are designed to fire .38 ACP and 9 mm Largo ammunition, but NEVER .38 Super.