eatures:1. Ear listen Through Wall Device Bug Eavesdropping Wall Microphone Voice Bug. 2. Listening through walls. 3. Special pull back vehicle with secret listening device. 4. Easy to listen all the action. 5. High sense metal probe. 6. Coming with earphone. 7. Small as a jelly. 8. Complete function:charge hole,earphone hole and switch knob upside. 9. Easy operate,cling to the door,window or wall. 10. Able to get the sound out from the wooden/brick wall, windows or door or armor plate. 11. High sensitivity detector. 12. Can be used for recording pen. 13. How to use: 1) Clockwise turn the master switch to start the device 2) Adjust the volume until you hear the sound clearlyProduct Parameter:1. Cunsumption current:10mA 2. Usage battery:9v batteries 3. Four sections audioes choicde A section 200Hz B section 800Hz C section 1200Hz D section 2000Hz 4. Measuring element sensitivity: -70db 5. Highest audio enlargement multiple: 2X 6. Penetrate sex:Cement wall,steel wall,wood wall,Iron wall,glass,cavity brick 7. Monitor style:Earphone, can outside meet speaker 8. Record style:Have export hole can outside meet record 9. Working temperature: -20-50 10. Weight: about 140 g 11. Size: about 43 * 36 mm/ 1.69 * 1.42 inchesPacking List:1 x Ear Listen Through Wall 1 x Earphone 1 x USB Cable