Polycom SoundStructure SR12. Input impedance: 10000 Ом, Analog input gain: -20 - 64 dB, Maximum input amplitude: +20.4 dB. Output gain: -100 - 20 dB, Maximum output amplitude: +23 dB, Output impedance: 50 Ом. Audio connections: 3.5 mm. Input voltage: 100 - 240 V, Input frequency: 50/60 Hz. Weight: 5.5 kg