Sensitive negotiations in your own boardroom should stay in the room. Set this unit on the table, flip one switch, and its ultrasonic field distorts what phones, pen recorders and other microphones nearby record.

• Built for medium to large rooms: 360° interference, rated by the maker for up to 8 m.
• One switch: a single on/off toggle starts and stops it, with nothing to set up.
• Up to 4 hours a charge: a 9800 mAh, 12.6 V rechargeable battery covers a long meeting.
• Table-sized: 25.4 × 11.4 × 10.2 cm (10 × 4.5 × 4 in), small enough to sit beside the water jug.

Good to know: cameras still record pictures; only the sound they capture is affected.