A stethoscope is a medical device for listening inside the human or animal body. Doctors and veterinarians use this device to check heat beats per minute as well as the healthiness of the lungs and heart.
Some GPS do have a microphone and listening device. Some GPS do not have this.
Yes.
speaker
when listening to your heart, lungs and sometimes stomach
Ear
Listening to music from an ipod/mp3 device.
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Listening devices (aka: 'bugs') are said to be vulnerable to the playing of sound or music from other sound producing devices (TV's - radio - players - etc) but I cannot assure that this is 100% correct.
An electronic listening device designed to be used in a briefcase or small bag.
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It was Lewis Nixon who invented the very first sonar-type listening device in 1906.