Artifact Spotlight! The Pitney Bowes Model K was the most common stamp cancelling machine used by the Army in the European Theater during WWII. The machine marked postage with indelible ink to indicate it had been cancelled. Watch our wonderful volunteer, Gerald, describe how this artifact works. Special thanks to our colleagues at the US Army Adjutant General's Corps Museum who contributed this piece for our 6888th exhibit. U.S. Army Training and Doctrine Command U.S. Army Combined Arms Support