... Power Max 4dBm* Speaker output power:* 19 Button design: 0-9 Keypad, MFB,Answer Key, Volume Button* LED Indicator Status: LED indicator light ... BC57E687BSpeaker8ohm, Maximum 1W,MicrophoneOmnidirectional, -42±3dBCharging interfaceMini8pin USBButtonKeypad, MFB,Answer Key, Volume ButtonRF Specification Frequency band2.4G ISM bandFrequency range2.402 ...