Always, always, ALWAYS post photos!!!!
I believe the origin of the Challenger name goes back to 1940 when certain Plomb socket sets were "introduced" as "Challenger" sets, though the tools themselves were still marked Plomb.
I'm not sure when the Challenger name started appearing on tools themselves, but it was certainly by 1951. They were "Fine Quality Tools at Popular Prices" - a "value"-line.
Challenger tools were also produced in Canada in the Proto plant in London, Ontario.
Challenger was one of the brands specifically mentioned when Stanley was busted for making false claims of USA production in the FTC complaint of 1999.
Stanley-Proto told a member here that production of the Challenger brand ended ~ 1998...