The built-in bias voltage of the 3.5mm interface is suitable for electret and other condenser microphone amplification, with a gain of 26.4db; Power supply: DC 5V-12V, built-in boost power module ensures the dynamic range of sound, working current: 5v-43ma, 12v-17ma; There are 2 output interfaces, 1.10K high-impedance interface, 2.600 ohm low-impedance interface, and three output terminal lines. Use 3 lines for dual-channel connection, and use 2 of them for mono-channel connection. Colour:green Material:plastic+metal Package Contents: 1 x Circuit Module 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.