Features 3 Output Ports: After the microphone and music are amplified, they can be output separately or mixed. There are a total of three output ports, and the mixed output port can directly drive the headphones to listen. Anti Interference: The amplifier is a stereo switch box, the signal is lossless, and the sturdy aluminum shell has strong anti interference. Many Compatible Devices: The 3.5mm interface of the amplifier can be used with electret and ordinary condenser microphones, and the 6.5mm interface is a dynamic microphone, which can amplify wired and wireless microphones. Good Audio Amplification: The headphone amplifier can amplify the dynamic microphone 6.5 port by 75 times, the 3.5 port condenser microphone by 22 times, and the stereo music input 3.5 port by 5 times. Compact Size: The stereo audio preamplifier is small in size, easy to carry, and can be used for audio amplification anytime, anywhere without hurting the sound quality. Specification: Item Type: Small Stereo Audio Preamplifier Material: ABS and Aluminum Dynamic Microphone: 6.5mm Condenser Microphone Interface: 3.5mm Power Supply: DC12V Power Connector: DC Approx. 5.5 x 2.1mm / 0.2 x 0.1in Package List: 1 x Small Stereo Audio Preamplifier 2 x Audio Cable Note: Please use a high quality low ripple power supply, as the power supply is not good enough to cause buzzing. Package List 1 x Small Stereo Audio Preamplifier 2 x Audio Cable