1. Polarization voltage board can be applied to other transistor front circuit boards, suitable for DIY use by friends with strong manual . 2. Single 60V output, +-60V dual output, dual +60V dual input, +60V and +120V dual output, can be according to the polarization voltage of the diaphragm, single output is suitable for single-layer membrane microphones, dual output Suitable for double membrane microphone head 3. It is recommended to use +60V and +120V dual output version. If you feel that the sound is not loud enough and the sensitivity is not high enough with 60V, you can switch 120, and you can connect a switch. Microphone type used: diaphragm, medium diaphragm condenser microphone (suitable for diaphragms with a diameter of 25mm or less) Frequency response: 40hz-16khz Sensitivity: -48db Output impedance: 250 ohms Maximum sound pressure level: 125db Signal to noise ratio: 60db Working current: 3.1mA Type: Polarization voltage board Type: Without Plug color:Red Material:PCB size: 45 x 16 x 9.5mm Package Contents: 1 x Circuit Board 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.