After the microphone and music are amplified, they can be output independently or mixed output. There are three output ports in total, and the mixed output port can directly drive headphones to listen. The 3.5mm interface with bias can be used with electrets and common condenser microphones, and the 6.5mm interface is a dynamic microphone, which can amplify wired and wireless microphones. The 6.5 port of the dynamic microphone is amplified by 75 times, the 3.5 port condenser microphone is amplified by 22 times, and the stereo music input 3.5 port port is amplified by 5 times. The power supply is DC 5-12V, and the rail-to-rail operational amplifier MC33202 is used. Please use a high-quality low-ripple power supply, as the power supply is not good enough to easily produce . The power interface is DC5.5*2.1, inside + outside - not include the power supply . Material: Metal colour: black Package Contents: 2 x MA-2S Audio Preamplifier Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.