Features: 1.Max sound out put:129±3dB 2.Sound gain:>= 40dB±5dB 3.Total harmonic wave distortion:<= 6% 4.Frequency range:350-4500MHz 5.Input Noise:<=32dB±3dB 6.Voltage:d.c.1.2V 7.Current:<=2mA 8. Full charging with about 2 hours 9. Working more than 40 hours 10. Working to both recharge by Magnetic Charge Dock Main Unit x2 Earplugs x8 Brush x1 User Maual x1 USB Charging cable x1 Charge dock x1 Gift bag x1 .