 Messerschmitt, needing products to build to keep his factories working, accepted the Fend 150, which was still being developed, and the Lastenroller, which was put into production.The development of the Fend 150 led to the production of the Messerschmitt KR175, which began in February 1953.Development continued after production began, resulting in 70 modifications of the design by June 1953.