$3.50
1. For a safely meaning like business negotiation and contract signing
2. Helps ensure the privacy of your phone conversations
3. Can effectively prevent eavesdropping, videotaping, fraud, protect personal privacy data and information confidential.
4. Fit for hotel / restaurant / public toilet / changing room etc.
5. Detecting frequency: 100-2600MHz
6. Effective range: 1-10m