Deutz AG
Approximately 23,000 RSO of all versions were produced by Steyr (2,600 pcs), Klöckner-Humboldt-Deutz AG (KHD; 12,500 pcs), Auto Union's Siegmar plant (former Wanderer; 5,600 pcs) and Gräf &amp; Stift (4,500 pcs).