The Shotgun Cartridge Factory of Székesfehérvár, had previously provided armaments for military requirements. Here, however, based upon an Italian pattern, an auxiliary single cylinder two stroke engine was produced, to provide additional power to standard bicycles.
Held beneath the pedal crankshaft, the rear wheel was driven via a small friction wheel, pressing onto the tyre. The original cycle pedals were retained to start the engine, support the power unit while hill climbing and in case of emergency breakdown (carburettor obstruction, spark plug fouling, etc.). Not only the cylinder, but even the piston of the small engine was made of cast-iron, and the output only just exceeded half a horsepower.
Even so, some 60 thousand DONGÓ auxiliary engine units were assembled, before production was discontinued in May 1957.