Smartcheater Wireless Invisible Spy Nano Earpiece With Bluetooth Neckloop - Cheat Exam The Bluetooth Neckloop 12 Hours Talking Time Battery! The Wireless Spy Earpiece has 4-5 hours talking time. Built-in Amplifier - 4 Watt (powerful sound) Bluetooth 4.0, support music trasmit Range to earphone - max. 80cm