Serene SI-UA-50 Universal Handset And Headset Amplifier

- Amplifies incoming voices up to 170 times (45+ dB), so you hear every word with unmatched clarity- Selectable digital tone enhancement allows you to boost and enrich the speech fequencies you can't hear well, making difficult to hear words intelligible again- Automatic gain control optimizes sound level for superior listening comfort- Easy headset/handset selection button for extra convenience- Latest digital sound processing technology eliminates virtually all distortion, echo effects and unwanted static commonly found in other ordinary amplifiers- Works with virtually all business telephones and headsets; it connects between phone's handset/headset and base- AC adapter included, battery (9V) optional