Observer

The observer is a quest item in Fallout 3.

Characteristics
The observer is a small video/audio transmitter that remains functional in mirelurk nests for extended periods of time. Moira asks the player to place the observer in a batch of mirelurk eggs in the Anchorage Memorial to observe their behavior.

Locations
Moira gives it to you when you accept the task of observing mirelurks during the second chapter of The Wasteland Survival Guide.

Related quest

 * The Wasteland Survival Guide