This is a great little math helper made by The Wolverine Toy Company, Pittsburgh, PA, USA. Wolverine was in business from 1903 to 1950. You push the handle to randomly selected subtraction problems. There is a plastic flap that flips us to show the correct answers. The front is marked "U.S. Pat. No. 2,310,898 which dates this from 1943 to 1944. It still works well and is in good condition. It measures about 4" tall at its highest point and is 6" x 7". Please email me with any questions.