Canadian Factories Build War Radios: sequence on "Sparks" receiving message, sending same to captain on the bridge. Two shots of a tank commander seated at the top of the turret speaking on the radio as gun fires. Cut to a US soldier speaking over the field radio. HAS of tank gun firing, as seen from the commander's position. Sequence in a radio factory of various components being made, parts being punched in large press, women selecting and shaping crystals. Several shots of men and women at work; several CUs of same. Shots of sets being tested for resistance to rough usage, being shaken, dropped. Shots of inspectors from armed forces inspecting radios and equipment. Final shot of record player being tested.