Earpiece working principle -
The tiny spy Earpiece ( electronic or magnetic ) is just a tiny device for producing sounds inside the ear by receiving EMW signals from any transmission module ( any Bluetooth module - Bluetooth neck loop , Bluetooth banyan, Bluetooth box Or any GSM-based product or any MP3 module ).
The earpiece alone can't work. It will need some transmission module for its working
A complete set includes everything - Earpiece Transmission module
 

Please do not buy if you are not having any module for the same. Its not like bluetooth earphones.
 
 
Cautions - 
Don't use this earpice for longer time. 8 to 9 hrs is maximum use time since it's electromagnetic ways might harm if exposed for longer durations. 
Never sleep with earpiece in your ear
Do not insert forcefully. Don't push the earpiece as they might harm your ear canal/drum. 
The buyer shall not use the product for any illegal purposes and shouldn't permit anyone to use the product in any kind of unlawful activities. We promote our products for betterment for our lives not to go against law, or humanity.