Features: 1. Protect the phone conversation from eavesdropping and listening. 2. Auto Stop telephone recorders from recording. 3. Prevent the telephone line from burglary. 4. Alert the telephone user from the third party intrusion. 5. 24 hour auto scan and ensure the telephone line in good working condition. 6. Suitable for touch TONE and PULSE telephone. 7. Compact design for easy carry and installation anytime. 8. No battery needed.