During World War II, on the site of a paper plant belonging to Letea company from Câmpulung-Muscel, the production of plane propellers and shooting equipment for airplanes produced by IAR Brașov was organized.

The 914 units of IMS-57 produced had the following characteristics: coachwork with two doors and tarpaulin, 3260 cc gasoline engine, 50 hp (37 kW) at 2,800 rpm, 80 km/h (50 mph), 24 L/100 km (12 mpg‑imp; 9.8 mpg‑US) consumption.

The construction was handicraft: the equipped chassis in functioning condition were tested on the route Câmpulung-Colibași where they were bodyworked, painted and finished in the Pitești factory UAP.

Launched two years later, the new type M59 signified a step forward compared to IMS-57: its engine had 56 hp (42 kW), a maximum speed enhanced to 90 km/h (56 mph), the manual windscreen wiper replaced with an electric one.

The M461 was a very good performer for its time, having won a few international competitions: 1970 Forests Rally (Belgium), 1973 Sons of Beaches (Oregon).