This is a recording microphone designed to look like a tie clip, along with a power supply unit. It requires a CR2025 coin battery (not included). I probably bought this over 20 years ago. Back then, I used to connect it to a voice recorder to record audio. As of now, I have confirmed that the power light flashes red briefly when a coin battery is inserted. I'm not sure if this is the correct operation. I don't have any equipment to connect it to, so I don't know if the microphone picks up sound. In other words, the functionality is unconfirmed, but I am listing it for sale. This item is not returnable. I have confirmed that the manual exists online. The following information was automatically entered by Mercari: ------------------ SONY ECM-T115 condenser microphone, with a convenient power switch and clip. - Brand: SONY - Model: ECM-T115 - Type: Condenser Microphone - Power: OFF/ON switch - Included Accessories: Clip