Bontempi Wireless Karaoke Microphone. Connect the microphone to a telephone, MP3 player or laptop via Bluetooth. The microphone is equipped with a smartphone standard and has an echo effect. Adjust the volume with the microphone or go to the previous/next song. The Micro USB connection and cable can be used to charge the lithium battery (cable included). Usage time: 3-4 hours. Charging time: 1 hour.