COOMAX Mini Spy Earpiece Invisible Earphone Cheat Covert Earpiece for Mobile Phone Completely hidden and discreet communication Works with any mobile phone with a 3.5mm jack or with the use of an adapter (not included) Invisible wireless earpiece receives signal by an inductive coil across electromagnetic fields (like a radio) Extra small wireless earpiece permits you to receive real time information or communications without being noticed. Earpiece Dimensions: 3x2mm