WHAT IS IT FOR - This audio bass level controller dial is an external way to adjust the frequency and gain output level from an amplifier, subwoofer, stereo system, equalizer or crossover volume form the dashboard or remote location. This amp level controller knob adds sub-woofer level controls or balances a multiple amplifier installation when you need quick adjustments without fussing with your graphic equalizer or stereo volume controls. COMFORTABLE TO USE - Compact housing allows the unit to be mounted virtually anywhere so control it at the user's fingertips. Simple in and out connections, no additional wiring needed. Great for a sub amp volume control. The controller enables you to adjust the gain level or volume of the device conveniently while driving. Just gently rotate the dial of the Frequency level and Gain level from this controller. Different frequencies can make the differently. DESIGN - Universal Car Audio Amplifier is made from high-quality materials for producing the optimal quality signal transmission. Four gold plated provides the resistance for noise and protects from environment interferences. The standard design allows to listen to the music in high quality sound. Mini size easy to install by DIY without manual, especially good fit for Car, Motorcycle, Speakers, Home theater. Simply connect the stereo output from your audio source device or car to the input of this controller and then connect the audio output from this controller to the amplifier. Output: 2 x Input: 2 x Frequency 150Hz - 40Hz Gain 0db to -12db Compatibility: It is universal Car Audio Amplifier. It is Suitable for most of . colour:Black Material:ABS size:5 x 5 x 3cm Package Contents: 1 x Car Audio Amplifier Only the above package content, other products are not included. Note: Light 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.