The Austrians built a number of vehicles like this, most of which ended up in German service from 1938 on of course. Only this one, the RK 7, also known as the Sd.Kfz. 254, went into real production, but there were also about fifteen RR 7 artillery tractors, which were converted into mittlerer Instandsetzungskraftwagen (Sd. Kfz. 254) supply vehicles by the Germans — not to be confused with the mittlere gepanzerte Beobachtungskraftwagen (Sd. Kfz. 254) which is what Dave has been building here.