Feature: 1. Tone Control: With this pre amplifier, you can conveniently control treble, medium, bass and total volume. 2. Broad Range: Enables 20‑20KHz wide frequency, and the tone control board also allows for easy adjustment. 3. Simple Using: Supports DC 12‑25V and AC 9‑18V input, and the installation is simple and quick to complete. 4. Smart Design: Through exquisite workmanship, ensures quick cooling and stable long working hours as well. 5. Stable Works: Uses 1.6mm thick board and whole process of spraying tin, energy saving and very efficient. Specification: Item Type: Pre Amplifier Material: PCB Input Voltage: DC 12-25V AC 9-18V. Structure: High, middle and low 3 sections continuously adjustable. Frequency Range: 20-20KHz Features: DC12V output. Input Interface: Approx. 54mm / 2.13in interface, approx. 5.08mm / 0.2in terminal. Output Interface: Approx. 2.54mm / 0.1in interface, approx. 5.08mm / 0.2in terminal. Adjustment Type: Treble + medium + bass + total volume. Installation: Mounting hole M3 (diameter approx. 3.3mm / 0.13in). . Package List: 1 x Pre Amplifier Note: Don't overload.