Features: High Sensitive Inner Ear Microphone Suitable for Mobiles and Office Phones Easy Handling with Retractable Cord - Batteryless Plug in Power System Electret Condenser Microphone Records the User's Phone Conversation to Connected Digital Voice Recorder Plug the Microphone Into the Socket and Use-No Installation Necessary Package Contents: Telephone Pickup Microphone Adapter Plug (3.5mm to 2.5mm) 2 Ear Cushions PouchYBS