Connection 1. Connect the controller output to the amplifier input. 2. Connect the car stereo output to the controller input. What this product does Provides a dedicated, front-accessible volume control for a secondary amplifier in a car audio system. Lets you adjust output level smoothly using a single knob. Key benefits — why you need it Gives direct control of a secondary amp without altering the main head unit settings. Makes balancing levels between the main system and an auxiliary amp quick and precise. Helps tailor perceived sound by allowing fine adjustments that affect how different frequencies are heard. Main features Simple, single-knob volume control for a secondary amplifier. Straightforward signal routing: car stereo → controller input → controller output → amplifier. Smooth, tactile knob operation — gently turn the knob to raise or lower volume. Compatibility and function Designed for use with car stereos and secondary amplifiers. Functions as an inline volume controller between the head unit and the amplifier, requiring standard audio connections. Performance notes Provides smooth level changes for accurate in-car volume management. Small adjustments can alter the balance and perceived tonal character because different frequencies react differently to level changes. Practical use scenarios Add a dedicated control for a subwoofer amplifier so rear passengers or the driver can adjust bass level independently. Install in a vehicle where an aftermarket amplifier is used for a separate audio zone and you want easy local volume control. Use when integrating an auxiliary amplifier for speakers that need frequent level adjustments without changing head unit presets. User guidance Make connections with the vehicle powered off, then test and fine-tune levels with the vehicle power on. Turn the knob gently to avoid abrupt level jumps and to find the desired frequency balance. Why this product stands out Focused on a single, practical function: easy, reliable volume control for a secondary amplifier in automotive audio systems. Minimal setup and intuitive operation for users who need precise, on-the-fly adjustments. Note: Follow standard safety and installation practices for automotive audio wiring when connecting this device.