This propeller, one of the first produced by Hamilton Standard, represented a major advance in aircraft technology. It allowed a pilot to adjust the blade’s pitch to provide the best performance at different air speeds—similar to changing gears in a car or on a bicycle. On takeoff the pilot chose a lower pitch to make the blade spin faster and provide maximum power. In flight the pilot switched to a higher pitch to make the blade spin slower and conserve fuel. The propeller is preserved in “used” condition.