2.4GHz wireless digital audio transmission; Audio-amplifying system; Convenient wireless design; Effectively reduces background noise; Noise-canceling & voice-clarifying technology; Auto Signal Control regulates & balances sound; Docking station charges hearing aid; Built-in 3.7V Li-Ion rechargeable battery; Up to 18-hour battery life; About 3.5-hour charging time; Over 50ft transmission range; Freq resp: 20Hz-15kHz; Universal size fits all; Tone, balance & volume adjustable; Built-in microphone for smartphone calls; Connects to TVs, computers, DVD players & more; 3.5mm audio, coaxial & optical inputs on receiver; Auto power off; Brown box packaging; Includes receiver docking base, wireless hearing amp, replacement earbuds, 3.5mm RCA connection cables, clip-on microphone extension cable, digital optical fiber cable, wall power adapter & USB charging cable;