Burndy Model MR8-39T

Anyone that ever used a pair of pliers to mangle electrical crimp connectors soon finds out that a proper connection is hard to make, a proper crimping tool is needed. They are not cheap. 
Not sure of the age of this one made by Burndy, but it appears to have came out of the Avro aircraft company which closed down in 1962 after the demise of the Arrow project. Burndy, however is still in business making electrical connectors and associated products.