Feature:1. SUITABLE MICROPHONE: Electret microphone amp input 3.5mm interface built in bias, can be connected to electret microphone head microphone or 3.5 interface capacitor microphone2. POWER SUPPLY AND OPERATIONAL AMP: Adjustable gain electret microphone amp power supply is DC512V, using the rail to rail operational amp MC332023. ABOUT INTERFACE: Sound preamplifier output adopt 3.5mm interface, can be connected to other sound device microphone interface or auxiliary, LINE and other line input interface, can not be connected to headphones listening4. OUTPUT PORTS: 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 listen5. GAIN AND POWER SUPPLY: Condenser microphone amp amplification gain 020db adjustable, built in 150mah capacity lithium battery, charging with mobile phone charger, once charging can be used continuously for more than 10 hoursSpecification:Item Type: Electret Microphone AmpMaterial: Aluminum alloyPower Supply: 3.7V lithium battery 150mahInput Interface: 3.5mm.Package List:1 x Electret Microphone Amp1 x Charging Cable