Feature: 1. Microphone Amp: High sensitivity, ALC automatic level control, 1000 times amplification, which allows you to hear weak sounds. 2. Practical Uses: Directly drive headphones to listen, can be connected to mobile phone recording, and the interface is 3.5mm. 3. Dependable Works: With premium aluminium alloy shell, small size and exquisite appearance, stylish and powerful. 4. Better Designs: This stereo switch box ensures lossless signal as well as strong anti interference performance, very reliable. 5. Smart Carrying: Comes with a compact size of 65 x 53 x 25mm, both the storage and carrying are very convenient. Specification: Item Type: Microphone Amplifier Product Material: ABS, aluminium alloy. Power Supply: DC 5V Interface: Approx. 3.5mm / 0.14in Battery: 250mAh 502030 li battery, with built in battery. . Package List: 1 x Microphone Amplifier1 x Power Cord1 x Headphone Cable Note: The product is only suitable for 3.5mm electret (2 pole, 3 pole) condenser microphone, and the REC port is a recording interface, which needs to be connected with a red cable to the product and recording equipment for recording, and is not used for directly inserting the microphone to output sound.