Allen electrical tester

With scales for 50 volts and 1000 amps, I'm not sure what this machine is for or when it was made. Allen Testproducts apparently used to make all sorts of engine and automotive test equipment, competing with Sun Analyzers and others. 
There isn't much about the company online except a mention that the division was sold in the early nineties to the SPX Corporation- which does not mention the brand in their website.