Directional Microphone
From the Metal Gear Wiki
Directional Microphone a microphone that allows you to hear quiet noises coming from a particular direction. it is unusual for a sensor in that it is under the weapons list instead of the items list in the survival viewer.
[edit] Usage
The Directional Mic is listed under weapons when it is equipped. The view is switched to first person view, with the Mic being held like a pistol. It can then be aimed to amplify sound coming from that direction. When aimed at a character their dialogue appears as captions, However the size of the captions depends on how well the mic is targeted at a character. So when eavesdropping on a conversation you have to make a compromise so you can hear both sides.
