"We have sold 5 of these in the last 3 months"

A Woodruff key is a small, semi-circular metal component used to secure rotating parts to a shaft. It fits into a corresponding keyway in both the shaft and the hub or gear, preventing relative movement between the two components. This ensures that the rotational force is transmitted effectively. Woodruff keys are commonly used in various mechanical assemblies, including motorcycle engines, to maintain alignment and proper function of gears, pulleys, and other rotating parts.