Dual continuity tester:

The article describes an instrument that is likely to become a standard unit in the toolbox of many electronics technicians. It functions not only as a standard acoustic continuity tester but also as a kind of wireless speedtester with which it suffices to merely touch the device to be tested with a finger. Its user friendliness is further enhanced by its knob-Iess switch-on system and an economizing automatic switch-off system.