Our wall contact microphone set is a professional device. We tried this mic out, listening through a wall and wow the audio is so clear. If an Ordinary wall contact microphone is not enough for your investigation, we recommend you our newest model. This is a multi functional wall contact microphone you can use it as a wall contact microphone and also as a wired remote microphone too. Features 1. Highly sensitive metal stainless wall microphone. 2. Chrome plating mirror finished stainless body. 3. Equipped with hollow needle mic(2 different types of needles). 4. 1 meter long wire remote microphone. 5. 25 meter long wire remote microphone. When you use a wall contact microphone please be careful not to scratch the wall. Otherwise it damages the needle of surface microphone. -NEEDLE MICROPHONE- One of the item characterizing this unit is its highly sensitive needle microphone. This needle microphone consists of a wired microphone and a needle. Enclosed is a wire microphone 1m long and a 25m long wire mic 2 different types of needle microphones are enclosed.