Features Preamplifier: This preamplifier board can condition the incoming audios signal before sending to the power amplifier board Intelligent Design: The preamplifier module adopts dual 5532 chips, which has good working stability and high efficiency Easy to Use: Preamplifier module is compatible with 2.54mm and 5.08mm connectors, and which the output is DC12V Good Control: Preamplifier module adopts continuous adjustment of treble, midrange, bass and volume, is very simple Simple Installation: This tones board comes with M3 mounting holes, which is easy to install and can be completed quickly in a few minutes Specification: Item Type: NE5532 Preamplifier Chip Model: NE5532x278M12x1 Input Voltage: DC 12-25V AC 9-18V Architecture: Dual 5532 High, Medium and Low 3 Stage Continuously Adjustable Features: DC12V Output Input Interface: Approx. 2.54mm / 0.10in interface, Approx. 5.08mm / 0.20in Terminal Output Interface: Approx. 2.54mm / 0.10in interface, Approx. 5.08mm / 0.20in Terminal Adjustment Type: Treble + Midrange + Bass + Total volume Mounting Hole: M3 (Diameter: Approx. 3.3mm / 0.13in) Material: PCB Package List:1 x Volume Control Board16 x Accessories Package List 1 x Volume Control Board 16 x Accessories