Listen through walls, hear conversations across the room. Add a parabolic reflector and
hear blocks away. The BIG EAR Audio Amplifier kit can be hidden about anywhere.
Makes an ultra sensitive intercom. Can be used as a .8 W amp. We
supply a mini-electret mike in the kit. You supply the speaker or headphones for output.
Power requirement: 9V Battery or 6 to 12v DC.
Printed Circuit Board Size: 1" x 2"
Here is the instruction sheet for the AA kit.