1. DC power supply 9 - 12 V
2. You can adjust the volume of the speakers with VR1.,
And adjust the sensitivity of the sound by adjusting VR2.
3. Can be integrated together more than two circuits. To increase the number of conversations
4. A switch SW1 button press to speak.
5. A switch SW2 button press to call.
6. A LED indicator circuit.
7. Power pole switch circuit is not a shock.
8. Dimension 5.1 cm X 9.58 cm (2" X 3.77").