As the saying goes, a wall has ears. You can hear some sounds from the next room if you put your ear against the wall. However, if you want to clearly hear the sounds from the next room, you can use this device for eavesdropping through walls. It looks like a stethoscope, but uses an electronic internal sound amplifier to amplify the sounds through walls, doors, windows and even steel plates. It includes an earpiece, a built-in rechargeable battery, and a volume switch. Eavesdropping is not a moral thing, so this device for eavesdropping through walls should be used under special circumstances. Its current retail price overseas is 62 US dollars.