After the end of WW2, Messerschmitt was temporarily not allowed to manufacture aircraft. And to remain active, it turned its resources to producing other commodities. In 1952, Fend approached Messerschmitt with the idea of manufacturing small motor vehicles, which were based on its Fend Flitzer invalid carriage.
The first of Fend's vehicles to enter production at Messerschmitt's Regensburg factory was the KR175 bubble car. The title Kabinenroller means 'scooter with cabin'. While the Messerschmitt name and insignia were used on the car, a separate company, incorporated as Regensburger Stahl - und Metallbau GmbH, was created to manufacture and market the vehicle.