The slender plastic probe above is the only tool I've ever encountered bearing the Cooper Tools name.
Originating in Mount Vernon, Ohio, the C&E Cooper Company was founded in 1833 by brothers Charles and Elias Cooper. Their foundry, the Mount Vernon Iron Works, produced ploughs, hog troughs, maple syrup kettles, sorghum grinders, wagon boxes and stoves. Eventually, they began to manufacture steam engines. Over the decades the company diversified immensely. In 1965, the company became Cooper Industries, Inc and two years later moved its corporate headquarters to Houston, Texas. Cooper acquired Lufkin Rule Company of Saginaw, Michigan, in 1967. It was the first of many acquisitions for what Lufkin president William G. Rector called a "tool basket"--a high-quality hand tools manufacturing group. Subsequent hand tool-related acquisitions included Crescent Niagara Corporation (wrenches) in 1968, Weller Electric Corporation (soldering tools) in 1970, Nicholson File Company (rasps and files) in 1972, Xcelite (small tools for the electronics industry) in 1973, J. Wiss & Sons Company (scissors) in 1976, and McDonough Company's Plumb Tool subsidiary (striking tools) in 1980. In 2001, it attracted a takeover bid from the rival Danaher Corporation. Eventually, in 2010, the two companies entered into a joint venture, forming the Apex Tool Group, an umbrella for more than 30 leading brands. In 2012, Apex was sold to Bain Capital for around $1.6 billion.