Features:<br> Just gently rotate the button of the controller. Different frequencies can make the song sound different. It feels very good and is very convenient.<br> Connect the RCA from the output of this controller to the amplifier, and wire the car stereo output to the RCA input of this unit.<br> Great for a sub amp volume control.<br> Used to adjust an amplifier's power level, stereo, equalizer or crossover volume form the dashboard or other remote locations.<br> Adds sub-woofer level controls or balances a multiple amplifier installation.<br> Compact housing allows the unit to be mounted virtually anywhere so control is at the user's fingertips.<br> Fine tunes the volume of any RCA line level signal you to control.<br> Simple in and out connections, no additional wiring needed.<br> Connect the RCA from the output of this Controller to the amplifier, and wire the car stereo output to the RCA input of this unit.<br> Specification:<br> 4 RCA: 2 RCA input & 2 RCA output<br> Level control knob<br> Frequency Range: 150Hz - 40Hz<br> Volume Gain Range: 0db to -12db<br> Dimensions: 48x56x41mm/1.89x2.2x1.61inch<br> material: plastic<br> Color as shown<br> Package Contents:<br> 1 x controller<br> Only the above package content, other products are not included.<br> 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.