The ERO is a Croatian insurrectionist submachine gun.
The year was 1991. The dissolution of Yugoslavia left Croatia with little weapons to arm their troops in time for said country's war of independence. An embargo prevented the newly formed state from legally buying weapons from across seas, which left Croatia with no choice but to design their own weapons, leading to the ERO. The weapon was designed to be a weapon to be used by special forces and combatants looking for weapons of this sort. The weapon, while based on dated designs, was apparently liked by its users.
At first glance, the ERO may appear to be a clone of the Uzi, however, the ERO is slightly different in some respects. The ERO is said to be made of better quality materials than the original Uzi, such as plastics, fabrics and metals, with earlier versions of the weapon having thicker barrels; in addition, the casing lid of the ERO is slightly wider than the Uzi. Mechanically, the ERO is identical to the Uzi.
As mentioned above, while the ERO is based on dated designs, it was apparently liked by its users; some even went as far to say that the ERO was even better than the Uzi it copied.
The Mini-ERO is a short version of the ERO.