The Baltimore AF B-10/34 was the first all-metal monoplane bomber to be regularly used by the United States Army Air Corps (and later American People's Army Air Force), entering service in June 1934. It was also the first mass-produced bomber whose performance was superior to that of the Army's pursuit aircraft of the time.
The B-10 served as the airframe for the B-12, B-13, B-14, A-15 and O-45 designations using Pratt & Whitney engines instead of Wright Cyclones. A total of 348 of all versions were built. The biggest users of the B-10/34 were the UAPR, with 166, and the Netherlands, with 121.