From Wikipedia: The history of the Allen Manufacturing Company and the rise of the world famous "Allen Wrench". In 1910, William G. Allen patented a cold drawing process for making hex socket set screws, pictured in the advertisement . These safety screws avoided the typical square head protrusion that was common of fasteners at that time. With this new design, a worker's clothing was much less likely to get caught on machinery and cause an accident. The revolutionary "ALLEN SAFETY SET SCREW" demanded a quality tool for turning the fastener. Hence, the Allen hex wrench was born in Hartford, Connecticut, USA. There have been many improvements to the tool over the years, resulting in the assortment of product you find in this store. The Apex Tool Group continues to manufacture William Allen's wrench in our facilities around the world, including Dallas, Texas, USA and Shanghai, China. The Allen(R) brand and products are owned and manufactured by us, Apex Tool Group, LLC, headquartered in Sparks, Maryland, USA.