Answer: Hat Stretcher. This vintage wood Hat Stretcher could increase the size of a hat in four directions. When you turn the metal disc with curved notches around the axis, four pegs move radially inward or outward. Learn more ››

Answer: Sleeve Arrow. The Ming and Qing Dynasties were the peak of the development of Chinese martial arts. Hidden weapons were developed during the Qing Dynasty. The Qing Dynasty was the last imperial dynasty of China, ruling from 1644 to 1912. This Sleeve Arrow was one of the most popular tool-driven hidden weapons. Learn more ››

Answer: Universal Extension Pedal. In 1919, the universal extension pedal, Rico, was the only device of its kind which fits every type or shape of automobile brake and clutch. Learn more ››

Answer: Portable Hand Force Pump. Patented in 1877, The Aquapult, or Portable Hand Force Pump, could throw eight gallons per minute to protect against fire, wash windows and carriages, water gardens, etc. Learn more ››