Abstract: A miniature, battery-operated electronic unit adapted to be attached to a common article such as keys or eyeglasses. The unit is responsive to a plurality of sounds for emitting audible tones to enable a misplaced article to be located. A sound detecting and indicating circuit provides the audible tones upon receipt of a sequence of sounds falling within predetermined frequency, time spacing and amplitude ranges. The correct sequence of sounds is generated by the user by clapping, whistling or making any other loud sounds, and no additional transmitting device is required. Improper sequences of sounds are prevented from producing false activation of the unit. Extremely low power consumption, resulting in part from CMOS technology, allows the unit to remain on continuously for a period of six to nine months using standard camera (button cell) batteries. Special battery-saver circuitry prolongs battery life.