I've only unearthed a small hand full of these tools over the years.
The Penens Corporation produced tools for the "Challenger" brand at Schiller Park, Illinois, at least up until the early 1960s. At some point, production moved to Cleveland. The Canadian side of the operation, Proto Tools of Canada, operated out of London, Ontario.
Proto eventually became part of the mighty Stanley Black & Decker empire. Below, my pair of Stanley Challenger pliers: