This amplifier has extremely low battery consumption operational battery life: not less than 2,000 hrs. It is also used for connecting Single-line or Multi-line phone.

FEATURE

Tx/Rx volume control Headset/Handset selection switch
Microphone mute switch
Busy indicator
Audio jack for external recording
Extreme low battery consumption (2*AA Battery)
Optionally AC/DC power adapter
Headset Hanger
85dB(A) receiver volume limitation (DA-475EU)