... .Sound Monitor,Audio Monitor 3.Good Quality 4,Wall Detection Wall Detection High Sensitive Partition Monitor, Wireless Bug Listening ... in case of damaging the machine. It needs to charge for about five hours. The sonde must smoothly stick ... times of amplifying the audio: 2000 timesPenetrability: Cement wall, Steel wall, wooden wall, iron wall, glass and air brickAnswering patterns: Headphones, recoding, ...