Sound remind once pairing

Set-in Li-ion chargeable battery                                                                                                               

Button control call back functionSNR: >75db

Output: 4.2V/500mA

Frequency range: 2.4G-2.480GHZ

Transmitting power(MAX): 4db

Receive sensitivity(TYP):-90dBm

Effective wireless distance: ≤ 10 meters

USB charging voltage :DC5V

 Battery :500mah